Pat yourself on the back, you’ve got another batch of wort and yeast doing its thing in the fermentor. With another brew day complete, it’s time for the cleaning to begin. Besides the brew kettle being grimy with spent hops and coagulated proteins, all-grain brewers are always faced with the sopping elephant in the mash tun. Those 10-20 lbs. of grain soaked up more than their weight. Today you can blissfully drop those 30 lbs. of grain down the trash chute before it makes your kitchen smell like garum, because we will be focusing on the other mash waste product: leftover sweet wort runoff, which you’ll have to drain before dumping the grains anyway.
If you use a continuous sparging method, you’re going to have leftover wort runoff. Even if you do let the grain bed run dry, chances are your mash tun has some sort of dead space where leftover wort can be found. You may think of these leftovers as a sticky mess waiting to happen, but consider this: it took you just as much time and energy to make those diluted dregs as it did to make the wort that was to be boiled, hopped, and fermented. So put it to use! Since wort is chock full of sugar you prodded enzymes into producing, use it the same way you would use any other sugar water. One of my favorite uses is for breads, since all that’s left is salt and flour. Generally, when I brew, I also make pizza. Here’s a simple recipe.
1 part wort
3 parts flour
For one medium crust, 1/3 cup wort and 1 cup flour will do, otherwise 1 cup wort and 3 cups flour will give you enough for two large crusts or three medium, depending on how thin you want them. I also like to use plenty of salt, about a tablespoon per crust. As far as flour choice, I like to use semolina flour, but bread flour or whatever you normally use will suffice.
So what do we do about the yeast? Bakers’ yeast and brewers’ yeast are the same species (saccharomyces cerevisiae), but produce much different flavor. After all, you don’t see beer being made with bread yeast (except maybe kvass style beer). Of course, that is also because bakers’ yeast isn’t produced under such sanitary conditions. Even regular doughs can get fermented with brewers’ yeast for a flavor twist (try some dry belgian yeast from your local homebrew store).
So bakers’ yeast will work with the wort (after all, it’s not going to be beer), or you could try reserving some of the yeast you pitched from your brew day – imagine the impact on flavor each different strain may have. You could always pitch with slurry from a previous batch, but you can also let it sit out and ferment spontaneously. Think sourdough. Think sour beer. This requires considerable more time, but the wort is obviously highly fermentable, so if you mix it, they will come. Just remember if you’re using brewers’ yeast, to have the wort 70° to 80° for good fermentation and flavor. For bakers’ yeast, 90° to 95° is good. A teaspoon of active-dry yeast should suffice for a cup of wort.
So how much sugar is in there anyway? Good question. You can get a sense of this by calculating the gravity. Take a reading with your hydrometer. Then, multiply the gravity units by the volume of wort (as expressed in terms of gallons) and then divide by the potential gravity of sugar to get a value that represents pounds of sugar in relation to density.
Here’s the equation:
(GU * V) / GUpot = W — where GU is gravity units (Specific Gravity minus 1, multiplied by 1000), V is gallons of wort, GUpot is the potential gravity of the substance you are figuring for, and W is the weight, in pounds, that you are solving for.
Here’s an example:
You have 8 ounces of wort which has a specific gravity of 1.010.
(1.010 – 1) * 1000 = 10 GU
8 ounces is 0.0625 gallons. Also, keep in mind, we are basically trying to figure out the density of the sugar water. If the only sugar in this liquid were sucrose, we could assume a potential gravity of 36 points per pound per gallon. Let’s run this equation.
(10 GU * 0.0625 g ) / 36 ppg = 0.017 lbs, or 0.28 oz.
So our liquid has the same density as if you had 0.28 oz of table sugar in 8 oz of water. This is the best way I have of imagining the sugar content in real terms. If you’re using dry yeast (especially rapid rise) the amount of sugar is a minor issue, it will rise like a lean yeast dough, with some sugar for the yeasties to munch on along the way. Note: specific gravity is the common method for a homebrewer, but if your hydrometer has a brix scale, that reading will tell you the percentage of sugar.
After scaling your ingredients, mix the dough using the straight dough method: take the dry ingredients and temper in the wort by thirds while mixing. Step 3 of yeast doughs is the actual fermentation. Cover the dough and put it in a warm place to rise.
How long does it rise? Normally, with an all sucrose/monosaccharide fermentation, a hour would be fine. According to this study, however, a maltose/disaccharide heavy wort at any given pH will take much longer to ferment. I’d say to give it at least two hours (longer with a starter), even overnight in the fridge to fully develop texture. The aforementioned study also shows that fermentation seems to cap out at around 70%. Also consider the fact that wort is made up in part by unfermentable sugars called dextrins (check out some numbers here), so any fermentation will have residual sweetness. Look out for lovely nutty and toffee-like flavor in the pizza dough. It will, of course, vary depending on the character malts that made up your grain bill in the first place. You can even add some bitter wort dregs from your brew kettle which will include hop flavor if you think you want that. The point is to experiment.
After the dough doubles and you are happy with its texture, treat it the same way you would any other dough. Punch it, portion it, round it, bench, shape, proof, and bake. I like to use a homemade white sauce or Don Pepino’s tomato pizza sauce (because it’s simple, natural, and flavorful) and a mozzarella/cheddar blend. Top with some peppers and onions and some smoked meat from North-South if you’re lucky enough to have it. Bake at 350° to 400° until golden brown around the edges and all the toppings are heated through or melted. Use your pizza stone, sheet pan, or aluminum foil however you normally would, that’s up to you.
All that’s left is to eat it. You don’t need me to tell you how to do that. Enjoy your beer-dough pizza!
Links I used:
On the study of glucose and maltose fermentation times (in relation to pH)
Wort composition and stuck fermentations: