Fermentation Gravity sampling question

[ToastedPenguin]

When I purchased my 6.5 G plastic fermentation buckets, I got ones with a drum tap on them figuring I could use the tap to remove a sample of the wort for testing without having to pop the lid to see if fermentation is complete. That is still my intent however I want to make sure I don't create any problems with the wort by assuming the use of the drum tap for convenient access to a sample will work as I imagined.

Has anyone used a a drum tap on a fermenting bucket to remove a sample or see any issues with using it during fermentation? The port for the drum tap seems high enough to keep any yeast from the yeast cake from being part of the sample. My big concern is adding oxygen bubbles when I turn the tap off.

Thanks!
David

 

[littleScrapper]

good question. i wonder if it would suck the water right out of your airlock...

 

[Legin]

...or the trub on the bottom. I'd be worried about disturbing the yeast cake.

 

[ToastedPenguin]

good question. i wonder if it would suck the water right out of your airlock...

Didn't even think if that...opening the tap might create a vacuum affect. Not an exact comparison but when I use one of those plastic beverage containers and don't open the top port it does exactly this. With something like an airlock in place it would pull from there I suppose. So maybe it wasn't a good idea after all

Guess I will just have to use the tap for racking or something....

 

[Hang Glider]

With the trub you would get, you'd probably be impacting gravity, unless you let that sample sit for a couple of hours - maybe cold crashing in fridge. And yes, it will draw negatively from your airlock.

something like this might work to replace your airlock - so it's clean air, but it will still be air - not CO2 - being introduced to that cover-layer above the surface of your wort.

 

[ToastedPenguin]

With the trub you would get, you'd probably be impacting gravity, unless you let that sample sit for a couple of hours - maybe cold crashing in fridge. And yes, it will draw negatively from your airlock.

something like this might work to replace your airlock - so it's clean air, but it will still be air - not CO2 - being introduced to that cover-layer above the surface of your wort.

I actually have a few of these filters I use with a SS stone and an aquarium pump for aerating my cooled wort prior to pitching the yeast. Might be an idea.

Realistically if I have to take a sample of my wort to see if fermentation has stopped after 7-10 days I would be popping the top of the bucket to do this, which introduces a lot of O2. Using the filter to keep the air clean while I take the sample from the tap might reduce the amount of O2.

As for the trub, assuming the tap port is the same height from the bottom of the bucket as say a beer thief when placed at the bottom when sampling, wouldn't the trub amount be similar? Or is the comparison based on when using a sanitized cup and grabbing from the top of the wort?

 

[thebigt85]

Personally I've never tried it, but I would be concerned with it being too close to the trub. Most of the stuff I brew isn't too complex yet it always seems to have a decent sized yeast cake. Popping the top on the bucket isn't really all that bad because the CO2 produced is denser than air, meaning that unless you're really rocking things or moving a lot of air while taking a sample you shouldn't have to worry about disturbing the CO2 blanket over the beer.

 

[Hang Glider]

and the yeast have thoroughly mixed the wort, so the sample at the top and the sample near the trub should be similar, discounting any actual trub accumulated - hence the cold crash.

 

[Pilgarlic]

So long as the hydrometer isn't resting on settled trub material, suspended material will not affect the gravity reading. This is counterintuitive for some, and thus it's always contested, nonetheless, it's true.

 

[ToastedPenguin]

So long as the hydrometer isn't resting on settled trub material, suspended material will not affect the gravity reading. This is counterintuitive for some, and thus it's always contested, nonetheless, it's true.

Based on what your saying if I removed the airlock temporarily, used an inline filter to allow clean air to pass through so no vacuum pressure occurs and take a sample from the drum tap, the hydrometer reading in the test jar would work even with some trub material that may settle to the bottom of this jar?

 

[Pilgarlic]

As long as your hydrometer isn't being supported from the bottom and is floating freely, you'll get an accurate reading regardless of suspended material. That's all I'm saying.