I brewed a big beer recently. My goal was to make a very big lager using an unusual technique -- using wort as my mash liquor and sparge water. And . . . it worked!

Here are the highlights of my brew day:

I mashed 12 lbs. of grains and flaked maize in my mash/lauter tun and collected 6 gallons of "light lager" wort in my kettle. This wort then became my mashing and sparging water, or mash liquor. My mash temperature was 151 °F, held for 20 minutes, yielding an OG of 1.044. I used a 5:1 mash thickness. I recirculated very briefly, then ran off the wort. I held the temperature at 151 °F, as best I could, the whole time (so the mash liquor would also be contributing enzymes to the main mash).

For the main mash, I scooped some of the mash liquor over to my HLT, leaving enough in my kettle to mash in around 6 lbs. of grain. The grains were Vienna, Pilsner and flaked maize, at a 5:1 mash thickness again. I mashed at 140 °F for an hour, 154 °F for 20 minutes, then mashed out to 170 °F. I then transferred the mash to my lauter tun, recirculated and ran off 5.5 gallons of wort, using wort as my sparge water (with 1.5 gallons of hot water used at the tail end of the sparge process). I boiled this down to 3 gallons in about 2.5 hours and had a wort around SG 1.120. I saved 1 liter of this wort in a sanitized media bottle to use as kräusen later.

The main thing I noticed about this process was that my boil time was greatly reduced. With the total grain bill of around 18 lbs., my normal procedure to hit a high gravity would have been to collect around 9-10 gallons of wort and boil this down to 3. This mostly likely would have taken 5-6 hours. The time spent in my brewday was, of course, at least partially offset by the added time mashing, but a shorter boil had one major benefit -- less color pickup. My 1.120 lager is several shades lighter than the equivalent 5-6 hour boil wort would have been.

I am very excited about the potential for this technique and will be experimenting with it further. When I get a decent amount of information, I will be writing about in BYO.

BTW, my Vienna/Pilsner lager turned out great -- one of the best lagers I've ever made. Too bad I've almost kicked the keg already.