Hydrometer Questions

[MJ82]

I am a noobie and I have read lot of stuff recently but cant figure out this question:

Just before pitching my yeast I stored a sample of my brew into the hydrometer tube, put the tube in the fridge to get it to 60 d F and then took my measurement (1.046 Initial). I then kept this sample and stored it next to my fermenter (I took the hydrometer out of the tube while storing). It's been fermenting for 3 days and I decided to check my reading. Since my room temp is around 70 degrees, I put the sample back in the fridge to drop to 60 degress and then take a reading. So the question is: When dropping the temp to 60 for reasons of accuracy, then storing the sample at room temp, then repeating this process over a few more times, does this affect my reading - changing the temp on my sample? Does dropping the temp and raising the temp affect fermentation? Am I not getting an accurate reading this way? Do I have to discard the sample every time and get a new sample?

I know its prob a dumb question but It would help me sleep at night if you could help.

Thanks

 

[JLem]

Are you talking about the same sample that you took BEFORE you pitched your yeast? If so, the sample can tell you nothing about the progress of your fermentation. With no yeast, the sample will not ferment and will remain at the OG.

Well...that's not true since it has probably become infected from being left out in the open and any number of wild yeast and bacteria are probably in there now. Either way, your sample is not an accurate picture of what is happening in your fermenter.

 

[MJ82]

Sorry, I mistyped that. I took my initial reading before pitching yeast and then 2 days later I took a sample and kept it in the tube with a lid. I want to disturb this fermentation as little as possible so I kept it in the tube and storing it next to the fermenter. To get an accurate reading I have to cool it to 60 degrees. Just wandering if checking this sample daily if cooling it and then letting it get back to room temp and then cooling it again to check it if it will become inaccurate because of the temp change. Thanks for responding.

 

[frazier]

There is little to be learned by checking a sample daily, unless you are accumulating data for a high school science paper (which would be a cool experiment, if I were in HS I would provbably do that).

Just wait until fermentation is over, then check a sample. I usually just let it sit three to four weeks, then bottle. I check a sample before bottling.

As far as temperature goes, you can check it at 70 degrees, and compensate for the temperature difference. Charts are available with a little googling.

No worries!

 

[BryceL]

What you want to do is take your original gravity (OG) which is before you pitch the yeast, it sounds like you did this. You can let it ferment for at least a week or until it looks like fermentation has stopped before you take another reading. Then you will want to take one more reading a few days later. If the gravity of the second and third sample are the same reading then it has likely finished fermenting and stable. If the second and third reading vary then it needs more time to ferment. You don't need to take a reading two days after pitching yeast since you can pretty much bet its not done yet and you will be wasting your beer. Take a new sample from the fermenter each time.