Hydrometer Tube Fermentation?

[chr15topher]

Hi guys! Pretty new to brewing over here and just had a quick question. I was watching some YouTube videos and I saw someone who added wort to their hydrometer tube after pitching the yeast. I was wondering what everyone's views on this are. He took his OG reading as soon as the wort was added so I can't see any fermentation starting to change the readings that quickly.. He then said that he'd cover the hydrometer tube up with some tinfoil and leave it next to the fermenting carboy so they have similar fermentation temperatures and they'd be subject to the same amount of light and/or temperature fluctuations. I'm assuming he did this so he didn't have to risk infection by only taking one sample.

My question is, is this ok to do? Will his readings be correct? Or is there a chance that the wort in the tube fermented differently then the wort in the carboy?

Again I'm pretty new to brewing and any input is appreciated. Thanks!

 

[petrolSpice]

Even though the test tube and the fermenter are near each other, it's silly to think they would operate at the same temperature. The test tube has far less volume and more surface area per volume, thus is much more sensitive to the surrounding temperature.

Thus they would ferment at different rates and perhaps come to different FG's.

 

[freisste]

It seems much more like the test to see exactly how fermentable the wort is. The process is this: after pitching yeast, take a sample and ferment "incorrectly" which is to say hot. This will allow the yeast to act quickly and ferment as much sugar as possible. The beer may taste like $hi+, but it's only a single diagnostic sample. Then take a gravity reading of the bulk beer and know how much more it could, theoretically, ferment.

I get the description you gave, but I agree with the previous post. Different enough to give different results. Although, there's a decent chance it's within measurement error, especially if a swamp cooler was utilized.

 

[dryboroughbrewing]

I've done this more than once, especially when I brew up something massive. You take a small sample, over pitch the daylights out of it, and let it rock and roll at a warm temp, this will let you know where your beer should be at FG, it's called a forced fermentation test:

https://www.wyeastlab.com/he-brew-qc.cfm

(under the 'wort' section)

 

[petrolSpice]

I've done this more than once, especially when I brew up something massive. You take a small sample, over pitch the daylights out of it, and let it rock and roll at a warm temp, this will let you know where your beer should be at FG, it's called a forced fermentation test:

https://www.wyeastlab.com/he-brew-qc.cfm

(under the 'wort' section)

If you overpitch the sample and ferment it at a high temp there is a very high probability that it will arrive at a different (and likely lower) FG than the actual beer.

If this was not true, then proper pitch rates and higher temps wouldn't be suggested at methods to get a beer to finish a bit lower, or to unstick a stuck fermentation.

 

[Dcpcooks]

If you overpitch the sample and ferment it at a high temp there is a very high probability that it will arrive at a different (and likely lower) FG than the actual beer.



If this was not true, then proper pitch rates and higher temps wouldn't be suggested at methods to get a beer to finish a bit lower, or to unstick a stuck fermentation.

It's a limit of attenuation test. It's more to see what are the lower threshold limits of your wort. It's a tool to see if your mash is on point. I have used it on new batches of beers. You can leave a sample in the tube but if you really want to see where your lowest threshold is I'd but it on a stir plate and keep it warmish, around 75-80.

 

[petrolSpice]

It's a limit of attenuation test. It's more to see what are the lower threshold limits of your wort. It's a tool to see if your mash is on point. I have used it on new batches of beers. You can leave a sample in the tube but if you really want to see where your lowest threshold is I'd but it on a stir plate and keep it warmish, around 75-80.

I see. Thanks for explaining that

 

[chr15topher]

Thanks for all the input everyone! Much appreciated. Seems like for my purposes I'll just take two separate samples. Thanks!