Double Trub-le

by Charlie Webster

For some time I’ve thought and talked about making a barley wine or strong ale from the first runnings and a small beer from the second runnings of a single mash. With my brewing time becoming limited, the holiday season approaching, and a shortage of homebrew on draft at my house, I decided to kill two birds with one stone and make two beers from the same mash.

The first step was to see if my mash tun would hold enough grain to make two batches from the same mash. I did this by first calculating the amount of extraction points I would require for each beer. For example, 5 gallons of 1.085 beer requires 425 extraction points and 10 gallons of 1.040 beer requires 400 extraction points. This totals to 825 points required. My average efficiency is 29 to 30 points per pound. Therefore it would require 28 pounds of grain to make both beers, well within the 32 pound limit of my system. The biggest problem is that with that much grain there isn’t room for the usual 1-1/3 quart of water per pound of grain. So I wasn’t sure if I could reach my desired efficiency, and I didn’t know if I would get 6-1/2 gallons of first runnings.

On brew day, I set up my gear and a kettle and burner borrowed from Bruce, and proceeded to dough in 30 pounds of grain. The mash went well, stabilizing at my desired 158 degrees, though it was thicker than I had hoped. After about 1-1/4 hours, my iodine test indicated complete conversion, so I started recirculating the runnings.

After recirculating about 2 or 3 gallons before things even began to run clear, I started running the wort into the kettle. Surprise, there were only about four gallons of first runnings in the mash tun. I hurriedly measured the specific gravity and determined that the SG was well over 1100, and I could add water to reach the necessary volume. After diluting the sweet wort with water, I fired up the burner and turned my attention to the sparge. Big mistake.

While I was getting the sparge going, the kettle boiled over, violently, depositing a gallon and a half of my precious first runnings all over the garage floor! I didn’t feel that I could dilute the wort any further, and so decided that I had to make do with a smaller batch.

While I was cleaning up the mess from the boil over, the sparge was proceeding normally. I took almost an hour to collect 10 gallons of second runnings and start them boiling. By which time it was time to start cooling the first batch.

Just as the first batch was finished boiling, the second batch was cooled and in a carboy waiting to be pitched. A little later, the second batch was likewise waiting for yeast. I pitched the first batch (destined to be my "Winter Warmer" holiday beer) with a packet of rehydrated Whitbread dry yeast, and each of the carboys of the second beer (destined to be my everyday drinking beer) with a packet of rehydrated Australian Ale yeast.

All told, from set up to clean up, brewing two batches took just over 8 hours, or about half again as it usually takes to make a 10 gallon batch. There was almost twice the amount of clean up, and about an hour more actual brewing time involved. Not a bad return on my effort.

As of this writing, I’ve not tasted either beers, though the second (small) beer was fermented out within 72 hours after pitching. The first beer is now in the secondary where it will take several more weeks to finish it’s work.

Brewing a double batch from the same mash is more effort, requires more grain and more attention, than brewing a single batch, but I think the results will be worth it.