Like many of us, I went all in on gardening this past spring and summer. As the days lengthened and rising temperatures thawed the last traces of a bleak New England winter, the collection of raised beds and fabric pots in my sliver of a backyard expanded.
The growing season in the Northeast is criminally short: Just a few months of full sun and warm weather—barely long enough for one flush of tomatoes. I tried growing everything I could get my hands on, from sprawling brassicas and purple snow peas to lemon cucumbers, baby melons, and all kinds of herbs—the weirder and more obscure, the better. But of all the plants I managed to grow this season, I was most surprised by my chile pepper plants. In May, I planted eight two-inch seedlings gifted from my next-door neighbor. By late August, I had hundreds of hot chile peppers: Crimson habaneros, conical Fresnos, tiny Thai Dragon peppers, aji amarillos, and Scotch Bonnets.
There’s just one problem with growing so many chile peppers. Unless I could use all of them in a timely manner, they would eventually turn to goo in my fridge. So I fermented them, and I made hot sauce.
Fermented Hot Sauce Versus Vinegar-Based Hot Sauce
Hot sauce is nothing new to the kitchen pantry. Every spice-lover has a mainstream favorite—to say nothing of the vast catalogue of mashes and pastes that includes condiments like sambal oelek, gochujang, or yuzu kosho. For the purposes of this article, though, I’m going to focus on puréed, pourable hot sauces.
Broadly speaking, there are two roads to hot sauce: vinegar and fermentation. Vinegar-based hot sauces like Cholula or Valentina can be as simple as blending chiles, vinegar, and salt for a vibrant, sharp, and punchy condiment. These sauces are generally shelf stable thanks to the pH-lowering benefits of the vinegar, which inhibits spoilage.
But what about fermentation?
With a little careful planning and time, making fermented hot sauce can be just as straightforward, and arguably more delicious. Many of the sauces you know and love are fermented, including standbys like Tabasco and Sriracha. Though "fermentation" might sound intimidating, it’s actually quite straightforward: Chop up some peppers, mix in some salt and maybe some water, and jar it all up. Over the course of a week or two, the pH of the mix will lower thanks to lactic acid bacteria (LAB) fermentation—the same process that’s used to make pickles, sauerkraut, kimchi, and other typically shelf-stable* crowd-pleasers. From there, you simply take the sour and tangy fermented peppers (a mixture called a"mash"), blend them up into a purée, and enjoy.
*Many fermented hot sauces also contain some additional vinegar to either bolster the existing acidity, or to lower the pH further for even more shelf stability.
So which method should you use to make hot sauce? I’d argue that, while vinegars are great tools for preservation, their use is akin to choosing a sledgehammer in place of a small mallet: One method (vinegar) is brutally effective, while the other (lacto-fermentation) shows finesse. Vinegar-based hot sauces tend to be one-dimensional in their flavor, and a bit harsh up front; the pepper flavor is raw—especially if you use it right away.
Fermentation, on the other hand, brings complexity and depth. It’s funk. "If you look at the classic Sriracha, and the Tabasco sauces—those are actually all fermented sauces, and they’re fermented for a minimum of one year, up to five," says Mara Jane King, a fermentation expert based in Colorado. The flavors of these fermented sauces are subtler and often more interesting than those in their vinegar-based counterparts—the slow, plodding work of lacto-fermentation transforms and tempers that raw spicy flavor over time, adding sour pungency and eventually contributing fruity esters and other organic compounds. Fermentation also takes some of the edge off harsh, aggressive spiciness, which can be a good thing.
Chile peppers are fruits of plants in the Capsicum genus, which can be traced back to the mountainous regions of Bolivia and Brazil circa 7500 BC. Though it’s hard to imagine Chinese, Korean, or Indian cuisines without the intense heat of fresh or dried peppers, it wasn’t until relatively recently that chile peppers came into more global use. In China, for instance, the first documented recipes to include chile peppers didn’t surface until 1790.
Today, though, chiles are obviously internationally popular, and most cuisines have developed some type of chile-laden condiment—often of the fermented variety. So it’s no surprise that hot peppers are ideal candidates for lactic acid fermentation. They’re relatively rich in the sugars lactic acid–producing bacteria eat, so fermentation proceeds quickly. And unlike other ferments like sauerkraut or dill pickles, which slowly dull in flavor over time once fermentation is complete, peppers can withstand much longer periods of fermentation without any detrimental effects to flavor. In fact, they benefit from it. "For pickles and fermented cabbage, there's a sweet spot," says Kirsten Shockey, a fermentation expert based in Oregon and author of several classic fermentation cookbooks, such as Fermented Vegetables at Amazon and Fiery Ferments at Amazon. "Past that point, the vegetable can break down and become unpleasant to eat. If you’ve ever had old kimchi or old sauerkraut, they start to oxidize, they start to taste sometimes metallic, sometimes dusty, musty, or mushy.* Peppers just get better the longer you wait."
*Despite their unpleasant taste and texture, these products are still safe to eat.
Of course, we can't talk about chiles without addressing the burn.
According to Dr. Paul Bosland, the director at the Chile Pepper Institute at New Mexico State University, there are at least 200 compounds that factor into the flavor of chiles. The most well-known compound is capsaicin. A chemical irritant for most mammals, capsaicin is part of a broader family of compounds known as capsaicinoids. The pepper plant produces capsaicin as a secondary metabolite—a deterrent against certain animals and fungi that would otherwise hinder its reproduction by over-digesting pepper seeds before they can be dispersed in the environment.
The burning sensation that we know and love occurs because we possess sensory receptors (TRPV1 protein receptors) on our tongues that detect excessive heat or scalding (think boiling water, or your hand touching a ripping hot skillet handle). Capsaicin binds to these receptors, and initiates a burning sensation due to the body’s reaction to nerve excitement. Technically, capsaicin doesn’t cause a chemical burn at all; it just feels that way. That biological sleight of hand—"the chemical stimulation of tactile nerves," as Paul Adams writes in Cook’s Illustrated—is known as chemesthesis. The irritation and inflammation that sometimes results can be very real, but the stimulus itself is not causing any harm.
From a cooking perspective, it’s useful to know a few more things about capsaicin and the other capsaicinoids.
- Capsaicinoids are hydrophobic. In other words, they are more soluble in alcohol or fat than they are in water. This means that a sauce made solely from peppers, water, and salt may tend to have more of an overall bite than the same sauce that has fat or oil blended into it instead of water; we might perceive the fat-free version having a harsher heat, while the fat-enriched one might carry a more moderate spice level.
- Capsaicinoids are slightly alkaline. Acids like vinegar and lemon juice tend to mitigate some (but not all) of the spicy effect; the same concept applies to lactic acid produced through LAB fermentation.
- Capsaicinoids are not the only determinants of a pepper’s flavor. A chile pepper is a fruit, and its true flavor comes from its composition of volatile compounds: esters (fruity aromas), alcohols (earthy and fruity), aldehydes (grassy), lactones (peach), and terpenoids (fancy essential oil). If you take away just one thing from this guide, just remember: Different chile peppers have fundamentally different flavors that have nothing to do with heat level.
The Hot Sauce Roadmap
So we've established what fermented hot sauce is and why it's cool. Now let's talk about how to make your own.
Step 1: Select A Style
Making your own fermented hot sauce requires making many small decisions about ingredients and techniques; in turn, those decisions will dictate the flavor and texture of the finished sauce. So it’s helpful to walk into things with a rough idea of what style of hot sauce you want to produce. Here are some broad categories to consider:
- Louisiana-Style Fermented Sauces: Often synonymous with American hot sauces, Louisiana-style fermented hot sauces are named after the birthplace of some of the country’s first commercial hot sauce brands such as Tabasco, Crystal, Frank’s Red Hot, Texas Pete, and of course, Louisiana Hot Sauce. They have a smooth texture that ranges from thin and watery to slightly viscous.
- Mexican-Style Sauces: Like Louisiana-style sauces, Mexican hot sauces are smooth and typically a blend of pepper types. Popular brands include Cholula, Valentina, Tapatío, and Búfalo. None of these brands ferment the peppers, but that doesn't mean they can't serve as inspiration for a fermented approach. Their consistency is generally thicker than that of Louisiana-style sauces.
- Thick Commercial-Style Sauces: Sauces in this category are thicker, and have less overall liquid incorporated into the mix. Think Sriracha (which is fermented), or any other sauce that has a ketchup-like consistency.
- Other Styles: Finally, you’ve got a virtually limitless array of sauces that fall outside of what is commercially popular. These include broken hot sauces that can be chunky or not emulsified; or even hot pepper mashes or pastes, which includes things like sambal oelek, gochujang, yuzu kosho, and doubanjiang. You’re really left to your imagination here.
Step 2: Choose Your Chile Peppers
Your choice of pepper(s) will have the most profound effect on the flavor and texture of your finished sauce. Sure, you could always throw a bunch of Thai bird chilies in some brine and YOLO it with Scoville units (and let’s face it, who am I to tell you how to live your life?). But sometimes it’s nice to be a little more deliberate.
Fresh Peppers Versus Dry Peppers
For starters, it’s helpful to select fresh peppers that have maximum microbial potential. Look for peppers that haven’t been surface-treated with pesticides, coated in wax or petroleum oil, or irradiated to extend their shelf life—all of which run the risk of inhibiting the growth of lactic acid bacteria. Organic peppers tend to check these boxes, but an organic label isn't a guarantee of that. Your best bet? Grow your own chiles or, if you can’t grow your own, find a friend who does. If you can’t find a friend, then look for a local farmer’s market or co-op. And if you can’t find either of those...then you go to the grocery store and roll the dice on commodity peppers (which will probably still work fine, but when the goal is maximizing your chances of fermentation success they're not your best choice).
There's some debate about whether dried chile peppers alone are sufficient for a reliable fermentation. Some claim a salt brine offers the perfect avenue for their fermentation: "As the brine hydrates the dried chile, any dormant microbes on the surface of the chile wake up," says Shockey. "Fermentation will initiate." But even Shockey recommends including some fresh material in the ferment to ensure a fresh source of surface microbes—fresh garlic, honey, or perhaps another fresh chile. Better yet, you could add some leftover brine from a previous fermentation, or unpasteurized yogurt whey (which is rich in lactic acid bacteria).
Nevertheless, using dried peppers opens up a new realm of distinct flavors. The drying process concentrates flavor and creates earthy aromas reminiscent of dried fruits. In some cases, dried chiles take on a brown or deep red appearance due to mild, non-enzymatic browning via Maillard reactions. And chiles dried with smoke, such as chipotle morita chiles, have an intense flavor that carries over into a finished fermented sauce.
No matter what peppers you choose, one thing is certain: Taste them first. I can’t tell you the number of times I’ve bulldozed my way through making jalapeño hot sauce without tasting the peppers first, only to find the finished sauce intolerably spicy or acrid. Don’t be like me. Tasting allows you to evaluate several criteria and offers clues as to how you might process the sauce down the line. Fresh peppers run the gamut in terms of spice level, texture, and flavor. Here are some basic (but important) considerations:
One of the first things you’ll notice when biting into a chile pepper is the heat. Some chiles, like habanero or Thai bird chiles, pack a serious kick. Others, like jalapeño or Anaheim chiles, are milder. Unless you’re a bit of a masochist, making a sauce entirely out of more extreme-heat peppers like, say, the Carolina Reaper, will likely produce unbearable results. It might be wise to to offset particularly spicy chiles with another ingredient (such as apples, berries, or carrots and onions) to temper that insane heat. If you want a hot sauce with a purer chile pepper flavor, you're probably better off choosing a milder chile.
Thick or Thin Skin
After heat, the second thing you might notice in a chile pepper is the thickness of its skin. Thin-skinned peppers like habanero, Fresno, or jalapeño chiles tend to have thin walls that are relatively easy to chew through. In contrast, thick-skinned peppers, such as some cultivars of cayenne or Anaheim chiles, have a tough outer skin that can be more difficult to fully blend, leading to an unpleasant final texture. Thin-skinned peppers generally produce a smoother sauce with minimal blending; they are well-suited to chunkier, broken-style hot sauces as well. Thick-skinned peppers benefit from peeling, straining, or aggressive blending to achieve a similar texture.
Thick or Thin Wall
The pepper wall refers to the amount of flesh under the skin in proportion to membrane and seeds. Jalapeño chiles tend to have thick walls with considerable water content. If you chop up or blend thick-walled peppers, that mixture tends to be juicy and watery, in absence of any added liquid. Thin-walled peppers like habanero or ghost pepper chiles have less water content, and if processed into a mash, can be dry without any added liquid. Counterintuitively, blended hot sauces made with more watery, thick-walled peppers tend to be slightly thicker and more viscous than those made from thin-walled peppers (assuming added liquid levels are equal in both cases). Why? Thick-walled peppers have more water, but they also have a higher pectin content; when they’re puréed, they release that pectin, which binds water and thickens the sauce. It’s the pectin in thick-walled chiles that gives Mexican chile sauces like mole poblano their smooth, creamy texture. By comparison, blending an equal amount of thin-walled peppers with liquid yields a slightly looser sauce.
Membranes and Seeds
Depending on the variety, chile peppers can be packed with seeds and white pithy membranes. While the membrane contains much of the spicy heat in the pepper, the seeds don’t contribute much heat at all. But in sufficient quantities, chile seeds can be bitter and give a gritty texture to a finished hot sauce. Peppers with significant white pith can also make a sauce taste bitter. To remove this bitterness, it can be helpful to remove the seeds and pith before fermenting. Otherwise, it might be necessary to strain the sauce later on to remove some of the seedy grit.
Speaking of bitterness, it’s worth identifying the actual flavor of the pepper—separate from the spiciness. In general, green or unripe peppers tend to be more bitter and grassy tasting overall. Red, yellow, or orange ripe peppers are usually sweeter and fruitier. Most people think chile peppers are all heat, but like any fruit, chile peppers vary in flavor and aroma—qualities that truly define a good hot sauce.
Click Play to See Us Taste Testing Peppers
Step 3: Prep Them Right
You’ve selected your peppers—maybe one variety, maybe a mix. The next step is to prep and process them. At minimum, it’s best to rinse and dry your peppers, in order to remove any potential residual wax coating or debris. Next, remove any woody stems; they offer little to no flavor (bitter at best), and have an unpleasant texture. If the peppers are particularly thick-skinned or seedy, it might be wise to use a vegetable peeler or paring knife to peel and de-seed them.
What about applying heat? Techniques like charring or roasting concentrate flavors and natural sugars, bringing out natural sweetness. Charring in particular adds a smoky element to sauces that persists even after fermentation—reminiscent of the smokiness of chipotle peppers. If you do choose to cook your peppers before fermenting, it’s important to remember that heat destroys microbes on the chile, so charred peppers might not be able to initiate fermentation on their own. To get around this problem, it’s best to set aside some fresh peppers (or some other fresh produce, as we’ll see later) to incorporate into the ferment. The fresh peppers act as a bit of insurance to increase the chances of successful lacto-fermentation. Lastly, if using cooked peppers, it’s wise to let those peppers cool before combining them with the fresh peppers; that latent heat can be detrimental to surface microbes.
Step 4: Consider Some Support Players
Some fermented hot sauces include supplemental ingredients in the initial fermentation step. You can add virtually any ingredient, from sweet fruits like berries and melons to vegetables and aromatics such as carrots, beets, garlic, and onions. Often, these additions are intended to balance the flavor and heat of the sauce. Here’s a quick rundown:
Fruits or Vegetables
Fruits or vegetables are useful for tempering aggressive heat, lending sweetness or vegetal flavors. Carrots, citrus, or berries are great examples. These ingredients are teeming with surface lactic acid bacteria, and are rich in natural sugar, which drives fermentation furter.
Ingredients like garlic or spices can bring more complexity to your hot sauce. Fresh garlic also helps fermentation, because it’s rich in surface lactic acid bacteria. Cumin, cinnamon, or coriander are great choices too: Their harsh, raw flavor melds over time as fermentation progresses.
For those concerned about garlic and botulism, let’s be clear: we’ll be using airlocks to ferment the hot sauces. This means that there’s oxygen involved that will gradually be replaced by carbon dioxide. High concentrations of carbon dioxide are inhibitory to Clostridium botulinum (which only proliferates in an anaerobic environment anyway); paired with the low pH produced by LAB fermentation, there’s no reason to worry about contamination and food safety.
Products like soy sauce, miso, and fish sauce are all umami-rich ingredients that can provide a welcome savory backbone. Despite being fermented, they don’t necessarily expedite the fermentation process; they’re pretty much done fermenting by the time you use them. If you do use these ingredients, you should factor their salt content into the total salt concentration of your ferment. You should also consider the timing." Don’t just throw in fish sauce or some garum at the beginning of [pepper] fermentation because it sounds cool," warns Rich Shih, a fermentation expert based in Massachusetts and co-author of Koji Alchemy at Amazon. "You might be better off blending in those products after fermentation, to get a more impactful umami flavor."
Step 5: Brine or Mash?
Perhaps the biggest decision when fermenting peppers is choosing between a salt brine or a mash. The goal here is to create an anaerobic environment to encourage LAB fermentation.
A salt brine is a solution of salt dissolved in water*. The primary advantage of a salt brine lies in its convenience: You don’t need to chop your ingredients too much (you can even leave them stemmed but otherwise whole), and as long they stay submerged in the brine, lacto-fermentation is almost guaranteed. Anything under the surface of the brine is deprived of oxygen. For some people like Mara Jane King, a salt brine is the go-to method:"I will typically go with a brine. It’s not so fussy. I start with whole chilies, packed into a container," she says. "I like to set it up and leave it—forget about it for a while." Salt brines are best suited for longer-term, set-it-or-forget-it fermentation, since the risk of mold contamination is lower. Others, like Kirsten Shockey, argue that a salt brine can sometimes mute the flavor of a hot sauce, since some of that flavor seeps out and into the brine over time (which later gets partially or fully discarded).
*Tap water can inhibit microbial activity due to trace amounts of chlorine or chloramine, so it’s best to use filtered or distilled water when fermenting. This is another advantage of using a mash over a salt brine.
At the most basic level, a mash (or solid state, or "dry" brine) consists of finely chopped or ground up peppers and salt. Chopping or grinding increases the surface area exposed to microbes, which is thought to speed up fermentation relative to fermenting whole vegetables. The salt draws out moisture, which ideally fills the spaces between the bits of mash to facilitate an anaerobic environment. For Shockey, a mash has a couple advantages over a salt brine. "I find that the flavors are so much more intense with a mash—especially when you age it," she says." Usually peppers are juicy [and release enough liquid], so why dilute that flavor?" In general, thick-walled, fleshy peppers are best suited for mashes due to their higher water content. On the other hand, a mash is a fussier technique.
“People have a hard time with mashes, because they’re hard to keep submerged [beneath the extracted water]," Shockey says. As carbon dioxide builds as a byproduct of fermentation, all that mash rises and can form a raft, which floats above the water. Since peppers have significant sugar content, they are susceptible to yeast growth in the presence of oxygen. Employing an air lock, frequent stirring or shaking, and careful monitoring are strategies to limit that growth. Airlocks keep oxygen out, keeping any raft that forms protected in a carbon dioxide-rich environment. Stirring breaks up an air pockets and keeps the pepper mash evenly dispersed in the extracted brine.
A third option is to combine a salt brine with a mash. In this case, the amount of brine is reduced, using just enough to fill the empty spaces in the mash. This technique is useful when dealing with thin-walled, drier peppers which don’t release as much water. The flavor here is still relatively intense and concentrated, although you still have to ensure that the mash stays submerged and monitor it for any yeast development.
Salt concentrations can range from 2% all the way to 10% in some instances. In addition to seasoning the ferment, salt inhibits growth of many microorganisms through osmotic shock, which draws water out of microbial cells via osmosis, effectively killing those microbes. Happily, lactic acid bacteria are salt-tolerant, so they are free to grow. For most pepper fermentations, there seems to be a sweet spot between 2% and 4%. At these slightly lower concentrations, fermentation is faster; it’s best suited for cooler temperatures, where microbial activity is slower overall. Higher salt concentrations are better suited to warmer climates or longer-term fermentations (longer than four weeks). For longer-term fermentations, Mara Jane King recommends concentrations around 5%. "If you’re gonna ask for something to be on the shelf for one to two years, then I think having a strong salt content is helpful to control mold and yeast," she says.
Step 6: Pack and Ferment
For successful fermentation, it’s helpful to choose a tall, narrow container with an airtight lid—glass, ceramic, or food-safe plastic are acceptable. Wide containers tend to be less practical, due to greater surface area exposed to air at the top.
If you’re using a salt brine, loading the vessel is as simple as dumping everything in. If you’ve opted for a mash, it’s best to pack the mash deliberately in the jar, limiting any pockets of air. The less oxygen there is to start, the better and more efficient the fermentation will be. Additionally, it’s helpful to leave a little headspace in the jar. As the mash ferments, carbon dioxide builds in the system, and the mash expands, rising higher in the jar.
Oxygen is the main enemy when it comes to limiting yeast and mold growth. The strategies here are multiple: For a brine, you can use a zipper lock bag of extra brine or fermentation weights to keep the chopped or whole chiles submerged. For mashes, you can cover the surface with plastic wrap and use fermentation weights; you can shake or stir the ferment daily to discourage unwanted growth; or you can sprinkle a layer of salt on the top surface to throttle microbial growth. But the most foolproof method is to use an airlock.
An airlock is any device that keeps carbon dioxide produced by LAB fermentation in the jar, while forcing the oxygen out of a one-way valve. Simultaneously, the airloc does not allow any oxygen outside of the jar back in, which ensures an anaerobic environment. Leaving a bit of headspace in the jar also allows carbon dioxide to collect in that space, which has a protective, antimicrobial effect on the surface. Mara Jane King is a firm believer in airlocks. "If I’m fermenting anything that the yeast is gonna want to play with, I’m gonna use an airlock."
There are several styles of airlocks. I used these at Amazon, which fit nicely on wide-mouth quart mason jars, but this type at Amazon, which Daniel uses for his sauerkraut recipe will work just fine as well.
Step 7: Monitor and Wait
You’re all set up. Your jar is neatly packed and sealed with an airlock. All you have to do is wait and let the microbes do the work. But how can you give yourself the best chances of successful fermentation? Here are a few things to look out for:
There is a glut of literature addressing the"ideal" fermenting temperature. But in practice, for most people, that temperature is your countertop—room temperature. "My first answer is always: Your counter is perfect," says Shockey. "That’s what you have." Still, a cooler temperature seems to be more advantageous. "I personally prefer a 60-degree ferment. I prefer a cooler ferment. 55-60 degrees is ideal. But who has a 55-degree space?" At higher temperatures, fermentation speeds up, but at a cost. "I find fermentation at higher temperatures to produce flatter flavors, flatter acidity. And in extreme cases, the fermentation is over in a day and half. It won’t taste as complex as a longer, cooler fermented product."
Timing: When is It Ready?
On average, fermentation is complete within seven to 14 days. At higher temperatures, that timing is even shorter. Ultimately, there are two reliable ways to tell if the ferment is ready and safe to eat. First, you can measure pH using pH strips at Amazon or a pH meter at Amazon. Technically, the FDA recommends acidified foods have a natural pH of 4.6 or lower. In practice, most commercial hot sauce producers aim for a pH level of 4.2 or lower, just to be safe. For truly shelf-stable homemade sauces, the popular standard for pH is even lower—3.4 or below.
You can also taste your ferment to gauge acidity. After a week, it’s helpful to open the jar and taste a small sample daily. "As soon as it tastes acidic, you’re generally good to go," says Shockey. "My palate has never been wrong. Ferments often go from this point of not tasting acidic—just salty and bland—to tasting acidic and sour. That’s not something to stress on."
The Case for Aging
Aging your ferment is optional. After the initial period of lacto-fermentation, you’re ready to make hot sauce. But you can also keep the ferment going in the jar—sometimes for years*. That waiting time is known as aging. After two to three weeks, most of the initial lacto-fermentation is complete, Shockey says. "[Fermentation] doesn’t happen anymore. But after that, compounds are changing. Phenolics add their own flavor, esters add their own flavor. Peppers are one of the few things you can age." She is quick to add that aging isn’t necessary. “Aging is the nerdy thing to do. But most people don’t need to do it." Still, it’s nice to know that you can. Moreover, aging doesn’t necessarily have to happen at room temperature. Esters and phenols continue to develop at lower temperatures—even in your fridge.
*The McIlhenny Company, manufacturer of Tabasco, is famous for aging their mash in white oak barrels for up to eight years. To celebrate their 150th year in business, their commemorative Diamond Reserve hot sauce was aged 15 years.
Addressing Kahm Yeast and Mold
“Whenever you are dealing with anything that is high in sugar [like peppers], you’re asking for yeast to join the party," says King. "Wild yeast can bring a lot of strange and weird flavors." King is referring to kahm yeast—a blanket term for the pellicle (layer) produced by yeasts and bacteria that grow when the surface is exposed to oxygen. Kahm yeast looks like a thin, creamy white, opaque layer on the surface of a ferment. It’s mostly harmless. In cases of minor growth, you can just mix the yeast right into the ferment and keep going. In other cases, the layer can grow pretty thick, so scraping away or removing the layer is a better option. But the best strategy is to limit exposure to oxygen in the first place, via an airlock.*
*Some might worry about opening up the jar to taste their ferment for flavor and acidity. Letting in oxygen could encourage yeast growth. But after a week or two, most of the fermentation should be complete: The system is acidified, and most of the free sugars have been metabolized. Under these conditions, kahm yeast has a much harder time growing.
Mold is another issue. If you see green, blue, black, or orange mold growing on the surface of your ferment, you don’t always have to throw it out. Just scrape it off if the growth isn’t extensive. The best strategies are to ensure an anaerobic environment, use fresher peppers, choose the appropriate salt concentration, or to ferment in slightly cooler temperatures (not exceeding 70°F).
Step 8: Post-Fermentation Processing
You’re in the home stretch. You’ve followed all the steps, and your peppers are nice and sour, with an FDA-friendly pH under 4.0. All that’s left is to blend everything up and call it a day, right? Not so fast.
If you’ve fermented your peppers in a brine, then it’s wise to strain out some or all of that brine before blending. Otherwise, you might end up with a watery, thin hot sauce that lacks intensity.* The simplest hot sauces are merely fermented peppers (and anything you may have added to the mix initially) blended with a small amount of brine. These sauces can have textures ranging from coarse and runny to smooth and thick, depending on the degree of blending and the amount of brine you use.
*In some cultures, the acidic brine itself is considered a condiment. In Hawaii, chile pepper water, or"Chili Peppa Watah" has a place on every kitchen table, and is used liberally on all sorts of dishes.
If you’ve opted for a mash, then you can technically stop there: That coarse-textured, fermented mash itself is a versatile condiment that can be spread, spooned, or easily incorporated into other dishes. But you’re here to make sauce. You’ll likely need to introduce some form of added liquid to your mash in order to blend it to a saucy consistency. That brings us to Step 9...
Step 9: Additives
Additives fall under two broad categories: Seasonings and additives to adjust consistency. When blended into the mix, these ingredients are meant to enhance flavor or improve texture.
The obvious choice for seasoning is salt. Often, a hot sauce benefits from added salt to bring out inherent flavors; this is especially true when fermenting at low salt concentrations.
Another common option is vinegar. Why would you go to the trouble of fermenting for natural acidity, only to add store-bought vinegar? Doesn’t that defeat the purpose? Vinegar—be it white distilled, cider vinegar, sherry, or fancy Banyuls—is rich in acetic acid, which brings a sharper, more pungent acidity that lactic acid can’t quite match. While LAB fermentation is important for funk and complexity, a measured amount of bottled vinegar can accentuate that natural acidity. Finally, adding vinegar can lower the pH of your sauce further (down to 3.4), which only improves shelf stability.
Sugar is another common seasoning to balance acidity. Purists may bristle at the thought of adding sugar to a pure fermented hot sauce (mainstream brands like Tabasco and Cholula have no added sugar). But I’m no purist. If you’re making sauce at home, season your sauce the way you want it. Keep in mind that adding sugar can encourage further fermentation, since it can be metabolized by established lactic acid bacteria. In this case, refrigeration is a good call, to prevent the bottles from building up too much gas as they sit.
You can also opt for fancier seasonings like soy sauce, miso, or fish sauce. These products add salinity and a pungent complexity to the sauce; they can also be particularly intense, so use discretion.
The primary method to adjust consistency is to control the liquid amount in a blended sauce. The more liquid you incorporate—whether it’s brine, vinegar, or soy sauce—the thinner your sauce will be. For a smoother texture, prolonged blending is your best bet. If you want your sauce even smoother, then straining that blended sauce is an even better option.
What happens if your sauce ends up a little too thin and watery? In industrial settings, it’s common to use additives like xanthan gum to thicken hot sauces slightly and to give them a glossier texture (Cholula is a good example). Xanthan gum is a polysaccharide derived from fermenting a particular bacteria; it typically comes as a white, odorless, tasteless powder and can be bought at most grocery stores (Bob’s Red Mill at Amazon is a common brand). Blending in as little as 0.2% xanthan gum by weight of the sauce is enough to produce a silky, smooth texture that doesn’t run all over the plate. Xanthan gum also helps to keep the sauce more stable (delaying separation over time), since fine particles are held in a thicker liquid suspension.
You can also blend in oil or fat to your hot sauce. Emulsifying fat into a sauce makes it richer and creamier; when added in the correct proportion, fat also thickens the sauce. A word of caution: Adding fats like olive oil or rendered animal fat can lower shelf stability, and can cause the sauce to harden when refrigerated. For this reason, it’s less common to find examples of commercially produced hot sauce blended with fat. It’s best to use a neutral oil like canola or vegetable oil—or even better, an infused one.
Step 10: Storage
At last, you’ve got fermented hot sauce. It only took a couple weeks and 4000 words of this guide. Storage is as simple as bottling. But what’s the best way to store your sauce? Technically, the sauce will continue to age over time and develop new flavors. If the sauce is kept at room temperature, there’s a chance that flavors may mellow, or colors may oxidize over time; higher temperatures will accelerate this process. To keep your sauce as fresh as possible, refrigeration is your best bet. If you really want to go the extra mile, you can heat treat the sauce by bringing it to a simmer—which kills any potential fermenting microbes—then bottle it and cap it with a hermetic seal (though heat can change the sauce’s flavor a little bit). Alternatively, you can add preservatives such as potassium sorbate and a sulfite to kill those microbes. But those techniques are beyond the scope of this article (and let’s be honest, kind of overkill in a home setting).
If you’re keen for a place to start, I’ve got a few recipes for fermented hot sauces that highlight different techniques in practice.
Double Berry Habanero Hot Sauce
This is a straightforward fermented mash recipe that capitalizes on the fruitiness of habanero chiles. It’s inspired by a Louisiana-style sauce—with a similar texture and tang. Because habaneros are thin-walled, dry peppers, I use a combination of blueberries and blackberries to add moisture and plenty of natural sweetness. The berries also temper the aggressive heat of the peppers, and are rich in pectin, which helps produce a smoother sauce. Bonus: The berries lend a vivid, crimson-purple color that looks great on the plate, or in the bottle.
Chipotle, Garlic, and Cumin Hot Sauce
Here’s a clear example of using a salt brine with dried chiles, that’s reminiscent of Chipotle Cholula in texture and flavor. Dried chipotle morita chiles, garlic, and toasted cumin seeds are fermented in a moderate salt brine. Over time, the garlic and cumin flavors mellow. I blend everything with a combination of brine and white vinegar, then thicken the sauce slightly with xanthan gum to give it a velvety, saucy texture.
Charred Fresno, Tamari, and Roasted Garlic Hot Sauce
This recipe employs a few different left-field techniques. Inspired by the bright chile and garlicky flavors of romesco sauce, it uses a combination of charred and fresh Fresno peppers, which are processed into a mash, then fermented in a measured amount of salt brine and tamari. I blend the peppers with vinegar and roasted garlic oil, which yields a smooth, creamy sauce with plenty of allium flavor.
Become a Pepper Shepherd
Making fermented hot sauce is empowering. And best of all, the possibilities are limitless. If you respect the process and foundational concepts, if you understand the microbes at work, there is plenty of freedom to explore flavor combinations and techniques. Kirsten Shockey uses the analogy of a shepherd. "The microbes are your flock. And let’s be honest: you’re not doing the work—the microbes are. You’re just providing the conditions for success. You put it together, you kind of forget about it, and it happens. I love that."