1) at what point is it best to do a diacetyl rest?
is it best to base it off of the amount of fermentable sugars left?
Generally I bung (by attaching a barby kuhner) and turn up the temp for D-rest between 2.5-3 days, or when i see the blowoff bubbling only every few seconds or so. Although this varies beer-to-beer and because i take into account ambient temp in the brewery, current gravity compared to target FG etc.. I shoot for a 2°F rise in temp for the rest which can be achieved by fermentation heat, or sometimes the ambient temp, sunlight hitting the FV can help too. Once you get to know your equipment and your beers you will get a good feel for it, i have worked on 6 different systems and they all have their own personality.
2) normally do you do the rest and then bung the tank or bung and rest?
After the rest fermentation should be complete, so bunging post rest would not give you any natural carb.
generally you want to build up a little natural co2 in the beer by bunging.
3) is there any chance of overcarbonating? should i just keep my pressure based on the temp of the beer to achieve 1.0 or so vols by lowering the pressure while the beer is crashed?
At ale fermentation temps it's highly unlikely you would overcarb the beer, if anything you would blow your PRV (or god forbid your FV)
4) after what point is it best to remove the yeast from the cone? (either to repitch or just remove it) or should it be left in there during the crashing phase and dumped prior to filtration or transfer?
IMO 5-7 days seems to be optimal for repitching. I always try to dump off the dead stuff before the new stuff floc's out. If your not repitching, dump it. After 7-8 days (max) dump it all, nobody likes the taste of dead yeast, yuck. Autolyzed yeast can ruin a batch of beer, dump that yeast.
5) after d rest, how quickly do you crash it? 3-4 degrees a day? slow at first then bigger increments?
I think there are various schools of thought on this topic....but, I will usually bring down to 50 the first day and then crash all the way the next. But in my case this system is undersized for our sales, and i don't have the luxury of conditioning for longer than absolutely necessary. Lager, what's that, seriously though I get to do one a year if i'm lucky and plan very well.
BTW most of these topics have been discussed at length at some point in the forum. The search function is a great tool.
Last edited by Jephro; 12-13-2008 at 10:23 PM.
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