I've made 3 berliners so far, and this third one had a very large pellicle on the mash. The method I use is brew in a bag, I'll mash at 145 for 45 minutes, cool the mash to 120, throw in 2 handfuls of unmilled grains, cover it with saran wrap and put the whole pot under the heat lamp. Well the first two had almost no pellicle at all, but this third one: The only difference between this one and the last two: 1. Didn't open it once to check sourness, I just go 5 days now. 2. Was closer to the heat lamp, and I rotated the pot every day. I tasted it, very clean sour, no off putting aromas, it's going to be a good one. I'm just curious as to why the pellicle was so much stronger this time around. I'm guessing it was the two things listed above but I have no idea really.
When you're pitching unmilled grains, you can't come anywhere close to saying "the only difference" -- who knows what you pitched in! You probably got a much different mix of bugs this time around.
Hmmm....makes sense never really thought of that but seems obvious now. I just used a couple handfuls of unmilled 2 row, it's the same 2 row I've used for the last two batches. It's just sitting in my cupboard in a plastic bag. For whatever reason it's produced a very desirable sourness 3 times now.
Yeah, sounds like a standard and good practice. You just have to remember you're rolling the dice a little . Maybe you pet your cat/dog? Maybe you sneezed on your hand? Or maybe the slight temp difference just let something in the mix dominate a bit more. As long as it tastes ok, since you're still going to boil it -- live is good!
Yeah probably the temp change I'd imagine. I dunk my hand in star san before grabbing the grains. I have another one souring right now, if it looks like this one in 5 days I think I can definitely chalk it up to the temp difference. Also I read that lacto fermentation creates no CO2, well something must be creating some kind of gas cuz that plastic wrap was puffed way up. You're right, since I boil the bugs it really doesn't matter as long as it's tasting good.
Something is definitely producing Co2. For the berliner that I did a few months ago, I put the wort in a better bottle with a solid cap on it to do the souring, and the next day when I got home from work, the cap had blown off and was halfway across the room. I'm pretty sure that exposure to oxygen is what caused the really awful vomit-y aromas that almost went away after the boil. I am keeping some bottles just to see if that ever cleans up, but I have the ingredients to take another run at it, so I think I'll just try again soon and use an airlock instead of the solid cap.
I'm sure there is some wild yeast in there, but I think lacto can produce CO2. Here is a post from @OldSock on brewing a Berliner weisse beer using 100% lacto. You can see in the accompanying pictures that there is quite a bit of gas production.
Batch I have souring now is already puffed up. Ran out of foil so I just covered the lid with a clean towel...forgot about the damn little hole in the lid though, realized something was different when I could smell it. The saran wrap is pushed against the hole anyways though so I think it will be fine but I used what little foil I had laying around to plug the hole. Interesting I'm getting such a clean sour from the grain. I remember reading about grain giving a better sourness than a commercial lacto culture. I've enjoyed my previous two sours so much I'm sticking with this method.
Well there are a massive variety of Lacto strains, but they do indeed pump out CO2. Note that not all of them pump out Ethanol, for example the White Labs strain (Lactobacillus delbrekii) doesn't but the WYeast strain (Lactobacillus buchneri) does. The former, however, is much better at producing lactic acid than the latter.
