I hate powdered sugar.
Its weirdly tinny flavor and tooth-aching sweetness add nothing but a choking hazard to most desserts, and with frosting, it's the pebble in my shoe: a pervasive grit that mars every bite. While I'll admit to keeping powdered sugar on hand in case of emergencies (disappearing in a cloud of smoke, temporarily blinding my enemies, detecting security lasers, et cetera), it's an ingredient I've always tried to avoid.
At the heart of this confectioner's complaint is cornstarch, which is added to powdered sugar as an anti-caking agent, a role in which it truly shines. Cornstarch is the least hygroscopic* of all starches, which keeps powdered sugar free-flowing and soft. (It also just happens to be the cheapest.) The problem is that it has a chalky taste and texture. This stems from the fact that cornstarch isn't soluble at room temperature. It may seem to dissolve in liquids, but the cornstarch granules actually remain distinct—like a fleet of Enterprise shuttlepods drifting through space.
*That is, it attracts the least water, the enemy of free-flowing powders.
Like finely tuned sensors, our tongues detect their presence as a subtle granulation, which is why every recipe that values smoothness—from pastry cream to mac and cheese—gets the cornstarch bubbling-hot. Around 200°F, its metaphorical shields begin to fail; the granules start to absorb water and swell, expanding until they cannae take anymore. If the heat doesn't let up, the granules eventually burst, leaving a debris field so finely dispersed, we can't perceive it at all.
That's what makes cornstarch so killer at thickening all manner of sauces and custards, but the thing about powdered sugar is that it's almost invariably served raw. Whether it's whipped into frosting or dusted over marshmallows, the cornstarch granules remain intact, leaving a chalky residue behind.
So, when organic powdered sugar first started cropping up in stores a few years back, I could only shrug. As far as I was concerned, it was simply a more expensive version of the status quo.
My hatred for powdered sugar blinded me to the fact that the push for organic would usher in the next generation of powdered sugar, altogether free from corn. See, in an industry dominated by GMOs, standard cornstarch is cheap, but organic cornstarch is hella expensive, motivating manufacturers to seek out cheaper organic alternatives, the most popular of which is tapioca.
A starch so objectively fantastic we speak of it as a jewel, throwing pearls into our tea for fun. If anything, pure tapioca (also known as cassava) tastes vaguely sweet, or at least pleasantly neutral. As a native starch—industry-speak for an unmodified plant starch—it feels silky-smooth even in raw applications, because each shuttlepod granule is smooth and round.
Unlike cornstarch, tapioca begins to swell and absorb liquids long before it's boiling-hot, providing greater thickening power in low- to no-heat applications. So, not only does tapioca-based powdered sugar feel creamier and smoother, it can help add body to no-cook desserts.
Take the frosting on my hot cross buns, a simple blend of cream and powdered sugar. For the sake of comparison, I omitted the vanilla and salt to observe each frosting's inherent color and flavor—not that the conventional version had either, just an unmitigated jolt of alabaster sweetness.
Though by no means runny, the cornstarch-based powdered sugar frosting slowly oozed to the edges of the spoon, and its texture reminded me of baking soda toothpaste. When made from tapioca-based powdered sugar, the creamy frosting was thick enough to mound up on itself and had a richer, more well-rounded sweetness. That's an enjoyable side benefit of organic powdered sugar, which is by nature made from raw cane sugar and therefore rich with the minerals and flavor we associate with molasses...complexity that tempers our perception of sweetness.
In granulated sugar, I find that flavor something of a distraction from the blank canvas I want for butter and vanilla, but it goes a long way in taming the aggressive sweetness of powdered sugar—a compelling reason to try organic powdered sugar even if you don't give a fig about the benefits of tapioca over cornstarch.
That said, tapioca-based powdered sugar isn't without its faults. Because it's so highly absorbent and so readily dissolved, it's pretty useless as a garnish for high-moisture desserts. Fifteen minutes after hitting a freshly cut lemon bar, even the thickest dusting will all but melt away, leaving only a few spotty clumps within half an hour.
Meanwhile, cornstarch-based powdered sugar barely breaks a sweat, making its stubborn refusal to dissolve an asset when it comes to presentation...and storage. Not only is tapioca more absorbent than cornstarch, it's more hygroscopic, which means it can suck moisture straight outta the air like some sort of culinary Kirby, resulting in a ton of lumps.
Unless you've left the bag open for weeks on end, sifting conventional powdered sugar is an effortless but largely unnecessary task, as most of the clumps will crumble away on their own. Not so with tapioca-based alternatives, which form enough lumps to make sifting essential. Every. Single. Time. I've repeatedly hoped that the sheer muscle of a professional KitchenAid would help me power through, only to end up with a lumpy frosting clogging my piping tip or ruining a parchment cone.
That extra step feels like a chore with powdered sugar's more utilitarian applications, when you just want to grab a handful and be done—say, rolling out a sugar cookie dough, or dusting marshmallows. But skip sifting and you'll find hard lumps of sugar embedded in your cookies and candies, as unpleasant to eat as they are unsightly.
For those of us who hate the chalky residue of cornstarch in powdered sugar, those downsides are a small price to pay, but if you've been happily baking with conventional powdered sugar all along, you may feel differently. Ultimately, whether you switch to organic and/or tapioca-based powdered sugar will depend on your baking style.
If you primarily use powdered sugar for decoration, whether sprinkling it over cannoli or mixing it into colorful royal icing, stick with a traditional cornstarch-based brand. Its bright white color, non-clumping formula, and resistance to melting will suit you best.
If you generally use powdered sugar as the foundation for buttercream, frosting, or glaze, try looking for an organic, tapioca-based brand. Its silky mouthfeel, mellow flavor, and ability to thicken give you more luscious results.
If you aim to keep kosher this Passover, organic, tapioca-based powdered sugar is corn-free by nature, so brands with kosher certification may help with holiday baking.
As a sworn enemy of powdered sugar, I can only say that the flavor and texture of tapioca-based formulas opened my heart, and pantry door, after two decades of fierce opposition. You may not experience the same sort of dramatic conversion, but experimenting with new alternatives can only broaden your understanding of this staple (and you'll be well supplied for all the powdered sugar–centric recipes to come).