I have always wanted to try a decoction mash, so I decided my Dopplebock would be the right place to start. Ended up being quite a long brew day.
The planned schedule was :
Dough in 20 quarts of 111 degree water to 16 lbs of 60 degree grain for a 20 minute Acid Rest.
Add 6.4 quarts of boiling water to achieve 122 degree Protien Rest.
After ten minutes, remove 40% of the grains, or 6.4 quarts of grain for the first decoction. Boil for 20-30 minutes and return to mash tun for sacchrification at 153 for 60 minutes.
Draw off 8 quarts or so after 60 minutes, boil and return to mash tun to mash out, and sparge with 6 gallons or so.
Collect about 8 gallons, boil for about 90-120 minutes or until down to 6 gallons.
Results: overshot the acid rest temp by a little under ten degrees, so I cooled down with a quart of cold water and let it sit outside with the lid off (surprisingly it did not drop much). The acid rest ended up being at about 104, which apparently is ok per Palmer. The infusion worked perfectly and I hit 122 on the nose. The decoction was a little tricky and I ended up scorching a bit in the middle of the pan at the end. I think I needed a little more liquid. The predicted 28 degree temperature increase from returning the decoction to the mash tun did not happen for some reason--I was close to 10 degrees short. So, I began drawing off hot liquid from the mash tun to boil to bump the temperature. At this un-opportune time i experienced my second stuck MLT in as many tries with my new mash tun. Bummer. Grain appears to be getting under the domed false bottom. I *eventually* fixed this and boiled about 6-8 quarts of wort to get up to my mash temp of 154.
From there everything went relatively smoothly. It took less than two hours to boil down to six gallons. The color looks good and the OG was about 1.080 so it looks like i did not have any conversion troubles. I am not sure what effect the extended protien rest or extended time at 135-140 before I could get up to mash temps will have on the final product, not to mention a significant amount of grain disturbance dealing with the stuck mash-tun after the decoction--probably will be a pretty cloudy beer. Hopefully the minor scorching will not impart any burnt flavors either
Bottom line is the step mashing and decoction probably added in the neighborhood of two hours to the process. Certinaly not something I want to endure each time I brew, but hopefully it ends up being tremendous. The interesting comparison will be that my buddy was also brewing a dopplebock with me but using a single infusion method. Should be a fun taste test in April.
Does anyone here regularly brew with decoction mashes? I am interested in results, tips, critcisms etc.