As Jadyn explained to inquiring commenters, the technique comes from a recipe for Surfer's Granola on Bon Appétit. A full cup (!) of hot tap water gets poured into a dry mixture of 2 cups of oats (and some optional millet and flaxseeds), then left to soften for about 15 minutes. You mix in oil and sweeteners, then bake for about 1 hour at 300° F.
As a die-hard clump fanatic (I pick out all the clumps from store-bought bags, then leave those individual oats for the losers who didn't get there fast enough), I wanted to put Jadyn's tip toe-to-toe with my go-to clumping method: egg whites.
So I made a double-batch of Surfer's Granola (to which I added some nuts) and split it into thirds.
To one third, I added neither hot water nor egg whites—this was my control. (I'm a scientist, you know.)
To another third, I mixed the hot water into the oats and dry ingredients, then added oil and sweetener.
And to the last third, I mixed everything together and mixed in an egg white as my last step.
I baked them all for one hour at 325° F and employed the method I always use to ensure maximum clumping action: Do not stir (at all!), then wait for the granola to cool completely in the oven before touching it.
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And clearly, my methodology works—all three sheets produced plenty of clumps! Even the control.
The differences were slight, and outlined below:
The control granola produced clumps that were the softest—the kindest on my teeth and jaw. The clusters were easier to break apart and there were still some loose oat pieces.
The version made with hot water was extremely crunchy and shattering: The whole thing was a sharp, cracker-like sheet with a shiny bottom that I had to force into pieces. Like brittle! And the next day, the clumps were even harder.
If you enjoy using your teeth like a hammer—and gnawing on biscotti—this might be the method for you.
And the last batch, with egg whites, was my favorite. The clumps had a nice sheen and were easier to break apart. They were less diamond-hard than the hot water clumps, though still a bit crunchier than the control group clusters.
So what's the takeaway here? I'd surmise that, if you're hoping for lots of clumps in your granola—whatever recipe you use—do not stir it. Let it cool completely. You're clump-bound.
And if you need extra assurance, mix in eggs whites; if you don't have egg whites (or if you prefer a jaw workout), use hot water.
Do you desire clumps in your granola? If so, what size and consistency? Tell us in the comments below!
A (former) student of English, a lover of raisins, a user of comma splices. My spirit animal is an eggplant. I'm probably the person who picked all of the cookie dough out of the cookie dough ice cream. For that, I'm sorry.