You may recall in my previous post that I ended up with 7.5 gallons of wort split between fermenters. You may ask, “But I thought you said you were brewing 8 gallons. Did you screw up your water calculations again?” Au contraire, dear reader. The missing half-gallon can be explained by a discussion of high gravity brews; or supplementing grain (which produced maltose) with simple sugars (corn sugar, beer sugar, inverted or “candy” sugar).
The theory goes like this: when given an option,yeast will opt to consume the simples and tastiest sugars available before breaking down more complex sugar like maltose. Sort of like children given the option of veggies or candy. They fill up on the yummy stuff and have no room for the greens. However, give them only greens first and somehow they miraculously have room for both plates.
My recipe for the Belgian Strong called for 15.5 pounds of grain and 3 pounds of simpler sugars (2 of candi and 1 regular corn sugar). If I had mashed the grains and then added the sugars to the boil (which I could have done and many people do), both sugars would have been present in the wort for the yeast at initial fermentation, when they are the most vigorous. My concern was allowing the yeast to consume the maltose before introducing the “candy” sugar. I was just listening to the Belgian Blonde episode of The Jamil Show yesterday morning on the train and he claimed that yeast lost their ability to consume maltose after two or three generations if fed exclusively on simple, short-chain sugars. So let ’em eat their broccoli before putting a plate of candy canes in front of them.
What got me was how would I know when the “main course” was nearing finish so I could boil up the candi sugar and introduce it to the fermenters. in a glass carboy, it would be obvious. I could take regular hydrometer readings, but I’m already running a little short on the volume. Well, I checked on the cornys this morning. Bubbling was very slow, so I suspected we may be nearing the end of the most active fermentation. I needn’t have worried about not knowing when high krausen ended because there was an obvious ring where it had fallen down. One batch looks to be clear (as in free of debris) liquid on top and there’s about an inch krausen ring above that level. The other has about the same with a little bit of junk still floating. They smell amazing! In the cooler water bath (just to even out temp changes), they only got to about 74. I pulled them from the water so they could rise a little higher and will boil and add the candi sugar tonight and move a small space heater into the bathroom to drive the temp up to around 80 during the day. Will follow suit in watching and add the last of the dextrose after the next rise and fall.
So there you go. I kept the volume to 7.5 because I knew I was going to boil the sugars in water and top them off. I should end up with 8 gallons or 8.25 after that. Mystery solved. M. Poirot and Capt. Hastings would be proud.