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100% Kolsch BIAB

Hello everyone,

New to the forums here. Was hoping to get a little friendly advice. I brewed my first all-grain on 4/8/14, which was the 3 gallon BIAB 100% kolsch. I had a starting gravity of 1.034, which was a little lower than required (hopefully it was either due to having more than the 4 gallon pre-boil or taking the sample directly from the top of the wort while in the fermenter). Either way, it calls for 1-2 weeks in the primary, 1 week secondary. With tomorrow being exactly 2 weeks in the primary, does anyone have any insight to what the spec. gravity or brix should be before transferring to the secondary? Or for debate purposes, is a secondary ferment even necessary? My only concern is that I have quite a bit of headspace in my 6 1/2 gallon big mouth bubbler so I am worried about some off flavors. I understand with it being my first all-grain there will be some undesirables and things to work out, but any advice from here on forward is greatly appreciated.

Cheers!

Alex

Welcome to the forum. I’ll be happy to offer advice, but I can’t promise it will be friendly. :twisted:

Attenuation for most AG beers is around 75%, meaning the FG = OG x 0.75. In your case, that means FG = 1.034 x 0.75 = 1.009 or so. If transferring to a secondary, you should do it when the beer is between 75% and 90% of the way to FG, meaning at around 1.015 to 1.011. Transfer any sooner and you have very little sediment drop so it isn’t worth it. Any later and there is so much sediment drop that you risk inducing a stuck fermentation. If you wait till FG is achieved, you might as well just leave it in the primary till it clears, as time is time and the yeast will eventually just drop.

Head space doesn’t cause off flavors, so that is not a worry. It can cause oxidation if you leave it there for a long time AND there is a way for the oxygen to enter the tank. I wouldn’t worry about that with a bucket or carboy if you have an airlock installed and you don’t leave it for more than a couple of months.

If I was making this beer, I’d leave it in the primary (forget the secondary) and cold crash it. Check to see if the gravity has stopped falling, and then put it in a fridge for a week or until it is clear.

Good luck, and there is no reason that you shouldn’t be able to get great beer even if it is your first attempt.

Thank you rebuiltcellars, that was friendly! :wink: . Great advice too for a beginner. So cold crashing it is just leaving it in the primary and putting it in the fridge for about a week, correct? I did take note of the gravity the other day, however those are in my notes at home and I at work currently so can’t check it at the moment. I think I might be somewhere in that range. Like I said, I am just worried that the OG was about .020 lower than what it should have been.

Cold crashing is putting it in the fridge after all fermentation is over. You can do that in the secondary, or you can skip the secondary entirely and just do it in the primary. That’s how I typically do it. I made a kolsch a few months ago, and simply left it in the primary for a month then kegged it. Came out crystal clear, and no off flavors.

If you are in a hurry, take a gravity reading after a week or ten days, and then again a couple days later. If it hasn’t dropped any further, it is done fermenting and you can put it in the fridge to cold crash. Kolsch yeast is notorious for taking a long time to drop out, so it may be a week or two after that before it is ready to bottle.

Alright I got home and checked my notes. Turns out on the 1st, so 4 days ago, my SG was 1.017, so an attenuation of 50%. I just checked it again a little while ago, same SG, 1.017. How am I only getting an attenuation of 50%? Any advice where to go from here?

Cheers!

Alex

That is much higher than expected. What temperature did you mash at?

[quote=“rebuiltcellars”]
Cold crashing is putting it in the fridge after all fermentation is over. You can do that in the secondary, or you can skip the secondary entirely and just do it in the primary. That’s how I typically do it. I made a kolsch a few months ago, and simply left it in the primary for a month then kegged it. Came out crystal clear, and no off flavors.

If you are in a hurry, take a gravity reading after a week or ten days, and then again a couple days later. If it hasn’t dropped any further, it is done fermenting and you can put it in the fridge to cold crash. Kolsch yeast is notorious for taking a long time to drop out, so it may be a week or two after that before it is ready to bottle.[/quote]

Just to clarify real quick on cold crashing… I was under the impression that putting it in the fridge with anything other than a source of CO2 hooked up to it would cause oxygen from the outside to diffuse inside as the pressure difference increased due to the temp drop. I know whatever CO2 is in the fermenter sits like a blanket on top of the beer as it’s heavier than oxygen, but will cold crashing with just an airlock create any extra oxidation of the beer???

[quote=“TrojanAnteater”][quote=“rebuiltcellars”]
Cold crashing is putting it in the fridge after all fermentation is over. You can do that in the secondary, or you can skip the secondary entirely and just do it in the primary. That’s how I typically do it. I made a kolsch a few months ago, and simply left it in the primary for a month then kegged it. Came out crystal clear, and no off flavors.

If you are in a hurry, take a gravity reading after a week or ten days, and then again a couple days later. If it hasn’t dropped any further, it is done fermenting and you can put it in the fridge to cold crash. Kolsch yeast is notorious for taking a long time to drop out, so it may be a week or two after that before it is ready to bottle.[/quote]

Just to clarify real quick on cold crashing… I was under the impression that putting it in the fridge with anything other than a source of CO2 hooked up to it would cause oxygen from the outside to diffuse inside as the pressure difference increased due to the temp drop. I know whatever CO2 is in the fermenter sits like a blanket on top of the beer as it’s heavier than oxygen, but will cold crashing with just an airlock create any extra oxidation of the beer???[/quote]
Based on ideal gas law, going from fermentation temperature to fridge temp would decrease the volume of the gas in the head space by about 4-5%, meaning that yes, you would pull in air from outside the fermentor so that the pressure would equalize, but only a small portion of the 20% O2 in that air would go into the beer. So not enough to worry about unless you are a commercial producer and you are trying to maximize shelf life for your product. This falls into the same category as hot-side aeration. Studies have been done that shows that HSA can impact the beer quality after long-term storage, but it is not something a homebrewer should worry about.

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