Inspired by my tasty berliner weisse experiences, in January I decided to try a no-boil experiment applied to one of my standard recipes. I scaled it down to one gallon, and altered it for the no-boil experience. This was a BIAB/No-chill/No-boil.
Anticipated issues to overcome, and how I resolved them
1) No-boil = DMS
Not necessarily. My understanding is that DMS is produced at 180 degrees, which explains why true no-boil berliner's don't have a DMS profile. As long as the mash and mashout stay below 180, it won't be a problem.
2) No-boil = no sanitation
Again, not necessarily. Pasteurization occurs at 160 degrees in just a few seconds, so as long as the mashout is above 160, no problems.
3) No-boil = low hop utilization
This is the one true dilemma with no-boil, in my mind anyway. Hop isomerization is greatest at boiling temperatures, but does occur to some extent at sub-boiling temps. I decided to use a 15-minute Cascade recipe for this, since there aren't bittering additions and it's more-or-less hop bursted. I moved all hop additions to the mash, since this is the one and only step in the brew day. Since this was no-chill, the hoppy goodness is exposed to the hot wort for an extended period of time, which may also help with hop utilization.
Original Recipe (5-gal)
1# crystal 60
3oz Cascade 15min
1oz Cascade 5min
No-Boil Recipe (1-gal)
2# 2-row (since there's no volume loss with boiling, I bumped this up to maintain OG of 1.055)
0.2# crystal 60
0.5oz Cascade mash hop
BIAB mash (including grain and hops) 60 minutes at 152 degrees
Mashout at 170 degrees for 10 minutes
Transfer to 1 gallon container, sealed up
Yeast pitched the next morning at 60 degrees
Primary for 2 weeks at 60 degrees
Bottle and condition at 60 degrees for 3 weeks
I seriously regret not taking pictures of this one, as it was surprisingly and unexpectedly clear; crystal clear. At least with the bottles I cold crashed for a day. I did open two bottles at room temperature, and these were slightly hazy. I was expecting it to be cloudy due to lack of hot break and cold break, and because I'm used to cloudy no-boil berliners. It was not sour like a berliner, but of course I didn't add lacto.
Surprising factor #2 was how similar to the original recipe it was. The no-boil had 'different' bitterness (see below), but otherwise tasted the same. It did have a thicker mouthfeel, perhaps because proteins/etc aren't lost to hot break? That's the best explanation I can conjure.
Surprising factor #3 was how bitter it actually was. Not as bitter as the original recipe, but it definitely had a hop presence. The original recipe had 36 IBU's. If I had to guess, I'd say the no-boil was in the low-to-mid twenties. In addition to the mash hops, you could also do a pseudo FWH addition by adding to the no-chill container, and you could always dry hop as well.
All in all, it turned out really good. However, there's still more experimentation to be done, and for my 5+ gallon batches I'm still doing my standard boil process, but I may soon make the leap and try a no-boil full batch. After reading Dave's post about his mash experiments I might try this again with a 40 minute mash. That would make for a really short brew day!