Sampling in Fermentor Bucket

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danath34

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Question about sampling the SG towards the end of fermentation. I have been worrying about possible oxidation considering the large surface area of beer that is exposed to air in a fermentation bucket as opposed to a carboy.

Let's say I don't plan on using a secondary fermentation.
Let's also say that I am planning on calling fermentation done when the SG is stable over a 3 day period.

That would mean that on the first day I sample SG, the CO2 above the beer will be gone, with a good amount of air in its place. If the SG IS stable over those three days, then I'll have 3 days of potential oxidation across this large surface area.

Seems like a lot of exposure to me. Or do you think this wouldn't cause enough oxidation to make a difference? Is there anything that can be done to avoid this?
 
New brewer, understandable, but you are being a little paranoid. I've only used buckets for primary and I crack them open to take samples, add hops or other additions. Even though the gravity is stable, disturbing the surface of the beer for taking the sample will cause CO2 to be released. Also remember that CO2 is denser than air so it will prefer to "stay" in the bucket as opposed to escaping.

End game, it's not enough to worry about. Don't violently splash the beer while you're getting a sample and it'll be fine.
 
CO2 is heavier than air. Unless there is a lot of heavy breathing the CO2 remains in place. Over a long period of time the CO2 layer on top of your beer and the gases in the atmosphere will reach equilibrium.
This equilibrium canl not be reached until CO2 is no longer being produced by fermentation of your wort.
The fewer times the CO2 layer is disturbed by taking samples, which can cause air turbulence, the longer the CO2 layer stays intact.
Considering the lengths of time for home brewing this equilibrium is not a concern.
I tried to work through Boyles Law once. That part of physics was not my forte.
Don't worry have a favorite snack or homebrew.
 
Wait 2 weeks before taking a first FG sample. It should be about done by then on average. Or close to it. I put spigots on my fermenters for this reason. Just remove & clean seperately before every brew & clean the mounting hole as well to help prevent infections. Re-assemble the spigot parts & fermenter wet with Starsan as well. Othwerwise,use a sanitized baster or thief to take the hydrometer sample. Doing so gently & quickly won't disturbe the co2 layer much.
 
thanks guys. I figured I was overthinking it.

I will probably get a turkey baster so as to not disturb the CO2 much. Though I like the idea of putting a spigot on the side of the fermentor to draw samples. I may do that one of these days.
 
thanks guys. I figured I was overthinking it.

I will probably get a turkey baster so as to not disturb the CO2 much. Though I like the idea of putting a spigot on the side of the fermentor to draw samples. I may do that one of these days.

That sounds like such a great idea, having a spigot to take sample from but one thing to consider, spigots occasionally leak. Since your beer will likely spend 3 weeks in the fermenter, think about how much beer can leak out with only one drop every 30 seconds. :(
 
That sounds like such a great idea, having a spigot to take sample from but one thing to consider, spigots occasionally leak. Since your beer will likely spend 3 weeks in the fermenter, think about how much beer can leak out with only one drop every 30 seconds. :(

It's a valid concern, although not bad enough to keep me from putting spigots on all of my fermenter buckets. Before transferring wort to one, I'll fill it 1/2 way with StarSan and keep an eye on it for any leakage. I haven't lost any beer yet and getting samples is much easier since I don't have to pull the bucket out of the fridge or pry off the lid.
 
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