What is your take on the value of decoction mashing especially dark german lagers? Recently I tried a hybrid decoction starting with dough in protein rest at 130F for 20, another infusion to 142F for 40 min then a thick decocotion, rest at 160F, boil 15 and adding to get mash to 158F for 20 min then a thin decoction to mash out, drain then batch sparge. (I'm limited to mashing in a 10 gal cooler.)
Secondly, how long is too long for fermentation? Many suggest going a full month rather than after reaching FG. Does this negatively affect the beer? Would lager yeast differ than ale yeast in this regard?
Lastly, for my hoppy beers, what is the most effective dry hop duration? I read a study that says 1-2 days is all you need. What dry hop method gives you the best aroma?
Thanks in Advance
Bob Manke -Kansasville WI
(1) I *love* decoction mashing my German lagers, especially the dark ones. Yes, you can get similar flavors by playing around with your grist, but I generally like the mouthfeel of decocted beers better. However, I haven't done any blind tastings or other experiments to see if that's something that I believe to be the case, or that is actually true. I really like decocting my German wheat beers too; there's a definite mouthfeel advantage that I perceive from those beers.
Your decoction technique sounds fairly similar to what I do, except that I can direct fire my mash tun so I don't have to infuse to go from 131 to 145 (my choices for rests), or decoct to mash out. The main decoction I do is the same as you; while you are resting in the mid 140s, pulling a thick decoction to get to the high 150s. I think that gives you the most impact for the least time. It's the basic hochkurz technique I describe in the book. I try to do a decoction for most German beers whenever I have the time.
(2) How long is too long for fermentation? When autolysis starts. That is more a function of temperature and time than just time alone. Higher temperatures force the yeast to try to be active, and they cannibalize themselves if given the chance. You can tell this happens when you start getting more of a glutamate flavor in your beer (like adding MSG). Generally, I don't worry too much about leaving my beers on the yeast unless it's hot. When the beer drops bright in the primary, fermentation is done and the yeast have flocculated. Time to rack. Some yeast take longer than others (some Belgian strains need the extra time to clean up after themselves), and other yeast will drop like a rock (I'm looking at you, 1968). I don't transfer based on gravity unless I'm trying to do a secondary fermentation or lagering. I generally wait for it to finish, and then drop bright. That's for ale yeast. I don't expect lager yeast to drop bright until lagering is done, and even then they often need help. I'm more likely to transfer to a secondary when the yeast are still working since it reduces the chance of oxidation. However, most of my batches just go from primary to keg, so getting them bright is important to me.
(3) Regarding dry hopping, there is a big difference of opinion. I don't use the technique too often since it tends to make a mess of clarity. However, when I do it, I try to limit the dry hop contact to 7 days. Some say that you can go 2 or 3 days; that's probably fine too. You can also dry hop multiple times, if you want. I just worry about oxidizing my beer with all that cold side work. So I tend to go 7 days with all my dry hops. I think the best aroma comes from a combination of whirlpool hops (steeping at knockout) with dry hops later. They aren't direct substitutes, but they each give a nice complementary character. If you want the best aroma, I'd use both techniques. I think the duration of dry hopping is of secondary importance, as long as you're talking about keeping it under 2 weeks. Keeping oxygen out of your cold side is critical, so keep that in mind as you execute these techniques. You can ruin that great fresh hop aroma so quickly with oxygen.