A few weeks ago, I was making risotto for dinner, using the pre-hydration method, which I'm so fond of for weeknight cooking. As I drained the Arborio rice from its bath of Sierra Nevada Glissade Golden Bock, now cloudy with starch washed from the surface of the grains, I had an epiphany.
The value of pre-hydrating starches (pasta, rice, etc.) rests not just in the speed of preparation (contingent, of course, on a little pre-planning), but in the possibility for flavor. I've taken to pre-hydrating rice and pasta in a wide array of flavorful liquids, from stock to the aforementioned beer, flavoring the grain from the inside. This yields amazing depth of flavor, with unique combinations possible. The only downside is the dump.
It always bothers me to pour all that flavor down the drain after the pasta has had its turn. As I stared at the hazy golden beer, I realized that this process could serve double duty. I'd been so focused on adding flavor to my starches that I hadn't ever considered the possibilities inherent in adding starch to flavorful liquids.
The starch in the liquid reaps the same benefit as the starch remaining in the grain - hydration. For preparations like risotto, in which a sauce is thickened by the starch from the grain being cooked, this is half the battle. With hydration out of the way beforehand, the only thing standing in the way of creaminess is gelatinization, wherein the already hydrated starch granules swell and burst, releasing free starch into the liquid, its hydrophilic nature lending body and smoothness at once.
I put this idea to use recently while making pasta for dinner. I hydrated some rotini in a combination of smoked pork and roasted red pepper stock and a little bit of dry vermouth. When the pasta was hydrated (about two hours), I drained it and set it aside, reserving the soaking liquid, now filled with hydrated starch granules.
I crisped some diced pancetta in a pan, browning a handful of mushrooms alongside, then deglazed the pan with the pasta soaking liquid, adding the pasta in as well, to finish cooking with the sauce. In short order (about four minutes), the pasta was cooked through, and the starch in the hydrating liquid had gelatinized, thickening the sauce and rendering it delightfully creamy, without the addition of even an ounce of actual cream. At the last minute, I added a cup or two of peas, just to heat through.
The sauce was elegant and creamy, but with a lightness and cleanness of flavor that wouldn't have been possible using a traditional cream sauce. While the fat in cream tends to coat the tongue and mask flavors somewhat, the "creaming" from the starch had no such effect. The sweet, smoky, and floral flavors from the soaking liquid shone through in the sauce, and came through in every bite of the pasta itself. It was quite possibly the best cream sauce I've ever made.
Now I'm thinking about other applications for hydration media, from deglazing and thickening pan sauces for steaks and chops, to the potential for nearly instant gumbo via the replacement of a traditional roux by the flavoring and thickening powers of this newfound ingredient. I've also just begun tinkering with retrograded starch, after unthinkingly freezing and thawing a batch of reserved hydration liquid. The gelling qualities of retrograded starch are ripe with possibility, if only I can figure out how best to employ it. And to think, I'd just been dumping it down the drain.