Done Fermenting? Time or FG Test?

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mrgrimm101

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Hi there,

I was just curious how many of you actually took gravity samples for 3 consecutive days to see if fermentation is complete, or if you just wait it out for a few weeks and assume it's done.

My first 4 batches I just waited for about 3 weeks before transferring or bottling and I've yet to have any problems. I have a stout in primary right now and I was going to give it about 3 weeks then I was going to bottle.

My fears with testing the FG 3 separate days are:
1.) Opening the lid and introducing any sort of contaminate.
2.) I don't know if I can just drop the hydrometer in the primary or if I need to draw out samples.
3.) If I need to get samples, 3 sample tubes worth of beer seems like a lot to waste that could be bottled.
4.) How do I draw it out? I have an auto siphon, is that what most people would use?

Thanks in advance for any help or advice.
 
Turkeybaster to draw samples.

Refractometer to measure over several days to see if it's done. You ony need one drop with a refractometer. The readings will be bogus but as long as they're equally bogus for every sample you draw you know that sugar is not being eaten and it's done.

Measuring is actually IMHO the only way to really know if the beer is done and to see if the fermentation is going as expected.

If you don't want to get a refracometer then just wait until you think its done, then draw two sampes over the course of three days, day "one" and "three. To be perfectly sure it's done you can't go without measuring it.

It's more beer wise economical to draw two hydrosamples than bottling too early and lose half the batch to bombs.
 
Considering that fermenation should be mostly done at this point, if not completely, how risky is it to remove the lid and extract samples? I'm just paranoid about introducing something to the beer that will contaminate the batch. I assume that the alcohol should help protect it.
 
The alcohol can't completely protect it at that point. Just be gentle when extracting the sample. And be sure there's no air flow around the fermenter when doing so. You want to keep as much of that co2 blanket in place as possible. Some o2 will be introduced, but is absorbed by the co2 to a point.
10 days to 2 weeks is a good time to check if it's down to FG. Wait till the 3rd day past that to check again. If the numbers match, it's ready to package.
I like to give it 3-7 days past when FG is reached to clean up any by-products of fermentation & settle out clear or slightly misty before packaging.
 
Don't worry to much about removing the lid.
Don't linger and make sure anything that is going to touch inside is sanitized.
Remember you now have alcohol in that bucket, which will help if anything does get in.
Again, don't worry so much about it, sanitize and go for it.
 
Thanks everyone, I'll go buy a turkey baster and take the first sample around the 3 week mark and the second sample 2 days after. Just to be sure.

Thanks again!! :)
 
For my first handful of batches I took samples to make sure it was done. After that though I usually just let the beer sit for 2 weeks and assume it's done. I take gravity readings when I bottle/keg just to see how much alcohol I made. I usually make American ales so I typically use sa05 so I sort of know where it's going to finish at. If it seems a little high I'll let it sit for another couple days but I've never had any issues with stuck fermentations or having it take longer than 2 weeks before packaging. Of course if I'm oaking, dry hopping, or doing some other kind of aging, this process will vary a little.
Like the others have said, don't worry too much about opening the fermentor. It's a necessary step in homebrewing and as long as you're careful you really shouldn't have any issues. I also use a turkey baster and it works just fine. If you can read the hydrometer then you could just drop it in your fermentor as long as it's sanitized but, personally, I'd rather just draw a sample so I can taste it too :tank:
With 3 samples you might minus 1 beer from being bottled but since you drink it it's not really being wasted.
 
For my first handful of batches I took samples to make sure it was done. After that though I usually just let the beer sit for 2 weeks and assume it's done. I take gravity readings when I bottle/keg just to see how much alcohol I made. I usually make American ales so I typically use sa05 so I sort of know where it's going to finish at.

I do the same thing. The key is to know your process, which means you actually have to take samples and test the first few times. If it's a new recipe, I test. If it's one I've done several times and I know I've got it down, I let it go 2-3 weeks, or whenever I get around it to, and keg/bottle.
 
Please don't return the hydrometer sample into the fermentor again. Even if you've star-saned the glass and hydrometer something can sneak up and die in it befor you noticing and pouring it back in, or other stuff. Such a small sample is not worth risking a whole batch getting sick, even if you are "sure" everything is sanitized. If (when) you get an infected batch, knowing you haven't returned samples you can eliminate that as a source of infection.

Like my dad said to me. Believing is something you do in church. Knowing is something you do IRL. Even if you believe a sample is uninfected when you pour it back in, you can't know 100%. Eliminate the risk.
 
Please don't return the hydrometer sample into the fermentor again.

I had definitely planned on not pouring it back to the fermentor. I've read many places to never return a gravity sample back to the fermentor. I was either going to drink it or dump it down the drain.

Thanks for the heads up though.
 
Chug! No seriously, just drink it until you sample enough to get an understanding of what the beer is like at that point in the process. Why waste beer if you don't extract some free (it's already pulled) data from it.
 
Hi there,

I was just curious how many of you actually took gravity samples for 3 consecutive days to see if fermentation is complete, or if you just wait it out for a few weeks and assume it's done.

My first 4 batches I just waited for about 3 weeks before transferring or bottling and I've yet to have any problems. I have a stout in primary right now and I was going to give it about 3 weeks then I was going to bottle.

My fears with testing the FG 3 separate days are:
1.) Opening the lid and introducing any sort of contaminate.
2.) I don't know if I can just drop the hydrometer in the primary or if I need to draw out samples.
3.) If I need to get samples, 3 sample tubes worth of beer seems like a lot to waste that could be bottled.
4.) How do I draw it out? I have an auto siphon, is that what most people would use?

Thanks in advance for any help or advice.

I've been doing what you did. I wait 3-4 weeks and bottle. I do take a reading when I bottle but just for ABV reading. I've never had a problem doing it this way in 2 years including a RIS and a double IPA.
 
Don't mean to take away from your thread grimm, let me know if you want and I'l delete this. Are there any downsides to pulling the sample from the spigot if I'm fermenting in a bottling bucket? The OG I took from the spigot seemed a little off.
 
Given how much the wort swirls and mixes during fermentation, it's hard for me to believe that the beer wasn't mixed well enough.

How far is it off? If you suspect it's not accurate, the only way you're going to be able to prove it is to take a sample from a different spot in the bucket. I really can't see any problem with using the spigot to draw a sample though.
 
I do take a gravity reading using a turkey baster on the day I plan on bottling or racking just to see where it's at, but unless it's nowhere near the expected FG, it's more just to make sure it's close. Never had a bottle bomb in 10 batches this way. I've always gone at least 2 full weeks between brewing and bottling and my beers are pretty much all session. If I did a stronger beer, I'd let it sit at least 3 weeks.
 
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