fermenting gravity sample...an interesting idea.

[RobWalker]

So I took my OG the other day and left it on the side. It's now fermenting along with my 5 gallons of beer!

Is there any reason why this wouldn't give you an accurate reading throughout fermentation without fiddling with the main batch?

 

[dennisking]

I would have thought the different size and shape of the vessels will have different results. Also are they being kept at exactly the same temperature.

 

[simonkidder]

That's great idea in principal. Wonder if it works? If you have a spare trial jar there's no reason why you can't check it using that method and normal method

 

[RobWalker]

That's great idea in principal. Wonder if it works? If you have a spare trial jar there's no reason why you can't check it using that method and normal method

Thats true, ill dig my old one out and give it a go when its halfway through.

There are a few variables, and nothing to say that wild yeast hasn't overtaken I guess. It's open topped, different size etc, but realistically its the same gravity and yeast, plus they started fermenting at the same time. Meh, we will see :)

They are at the same temp as they're in the same room, fermentation temp could be lower due to more heat being lost from fermentation itself.

 

[bones]

There is one test to be preform as a small sample from the main batch and thats a forced attenuation test..

That is that the small sample should be lifted in temperature from the main batch so it finishes first... about 25 deg ...then you will know far far the yeast will go..

So if the small sample finishes at 1012... do not expect the main batch to go any further..

 

[RobWalker]

ah, that's interesting! cheers. I'll definitely do that on the next one :)

As for this one, samples are reading roughly the same at around 1.020 so far. :)

 

[RobWalker]

So, all finished and kegged. They were kept at the same temp, the krauzen around the hydrometer made it difficult to read, but I did get a good general idea of how it was going, and the foam died down after fermentation giving me my FG reading, meaning all I had to do was syphon the beer into my keg. Saved a few difficulties I guess.

I suppose really when you consider that beer's a very obvious fermenter it's not really that much of a fantastic idea, especially since you need to leave it for a few days after fermentation to clean up after itself, at which point it's obviously finished and clearing out. That said, it DID stop me poking around with the main batch, so i'll be doing this from now on with my large beer batches. At the end of fermentation I couldn't get a tap reading because trub had found its way into the tap, so in that respect it works a treat!

I'd suggest it, if it's easy for you to do, which it probably is if you take your OG. :)