How to take multiple gravity readings?

How do you all take multiple gravity readings while the beer is fermenting (to make sure it's done)? Do you open up your fermenter each time? If so, what do you do to minimize the chance of an infection? How are you pulling the sample out?

I sanitize the hyrdrometer, pull the lid off (I use buckets mostly), and drop it right in. I've never had an infection from doing this. You could buy a wine thief if you're really concerned about it and that would pull beer out for you. You'll still have to pull the lid off though. Pulling the lid off your fermenter isn't going to cause any problems unless you're leaving it off for extended periods of time. A few minutes won't hurt.

Yes you open up your fermenter each time.

This is what I use, and it works with both buckets and carboys. I replaced the plastic one a year ago with an extra long stainless baster from a kitchen ware store and it is awesome. But the plastic one from any grocery store works fine.



And



Here's what I do....

1) With a spray bottle filled with starsan I spray the lid of my bucket, or the mouth of the carboy, including the bung. Then I spray my turkey baster inside and out with sanitize (or dunking it in a container of sanitizer).

2) Open fermenter.

3) Draw Sample

4) fill sample jar (usualy 2-3 turky baster draws

5)Spray bung or lid with sanitizer again

6) Close lid or bung

6) take reading

It is less than 30 seconds from the time the lid is removed until it is closed again.

Probably less if you have help. And unless a bird flies in your place and lets go with some poop, you should be okay.

Excellent info as usual. Thank you.

I think it's best to take it out with a wine thief or turkey baster so you can knock some of the residual CO2 out of solution, which could throw off your gravity readings. I usually pour it back and forth between the sample tube and a glass a few times.

A sanitized mug will work in a pinch too if you are fermenting in a bucket. I have baked some mason jars after carefully washing them so they are sterile (instead of just sanitized) and I carefully scoop out some beer with them. Allows me to really taste in a glass afterwards instead of just downing the test tube.

Don't bother with multiple samples, I test a batch once, maybe twice. Instead, I give it PLENTY of time to ferment (2-3 weeks minimum).

broadbill said:

Don't bother with multiple samples, I test a batch once, maybe twice. Instead, I give it PLENTY of time to ferment (2-3 weeks minimum).

Click to expand...

The whole point of taking multiple gravity readings over the span of 2 or more days is to assure fermentation has stopped, since there's no way to know exacty what gravity you'll hit when it does. Testing it once isn't going to tell you anything of value. You might as well not even bother.

I personally wouldn't feel too comfy just assuming a certain time-period (like 2-3 weeks) will be enough for complete fermentation, especially if I was bottling afterwards. MANY fermentations take longer than this.

broadbill said:

Don't bother with multiple samples, I test a batch once, maybe twice. Instead, I give it PLENTY of time to ferment (2-3 weeks minimum).

Click to expand...

I could not agree more.

While testing over 2 days or more does in fact tell you fermentation is complete without any shadow of a doubt, in most beers I make there is no real reason to bother with it.

100% of all beers I have made are fully done primary/secondary fermentation after 3 weeks. I just leave it on the trub for 3 weeks, rack it and bottle it. I only test just before I add the bottling sugar and I have never had a single problem. Even if I did, there is not a heck of a lot you can do about it anyway. Now, HUUUGE gravity beers are a different animal - but those are typically far and few between.

If I bottle after 3 weeks, my Diacetl rest is complete and my fermentation is always done. Why bother testing in the middle?

I just perfer simplicity - why make more work for oneself?

Anyway, to each their own. Brew on :rockin:

I've had a bock going for almost a month now. At 1.021 from 1.070 and I'm hoping it gets down to 1.017 or so. I'm taking at least one reading a week.

tunoffun said:

The whole point of taking multiple gravity readings over the span of 2 or more days is to assure fermentation has stopped, since there's no way to know exacty what gravity you'll hit when it does. Testing it once isn't going to tell you anything of value. You might as well not even bother.

I personally wouldn't feel too comfy just assuming a certain time-period (like 2-3 weeks) will be enough for complete fermentation, especially if I was bottling afterwards. MANY fermentations take longer than this.

Click to expand...

Read the OP....they specifically asked if/how they should take multiple hydrometer readings DURING fermentation. If its still fermenting, then I guarantee the gravity will be different from one day to the next.

Once fermentation is done, and giving it extra time on top (which you should do anyway)....one reading before bottling is enough. If you want...take two readings...I've never seen a drop in gravity at this point in the game so I don't bother.

broadbill said:

Don't bother with multiple samples, I test a batch once, maybe twice. Instead, I give it PLENTY of time to ferment (2-3 weeks minimum).

Click to expand...

I do the same. But I'm usually done fermenting in under 2 weeks (most ales). Basically as soon as the yeast drops it's done. I take a reading when I rack it to the keg for record keeping. I will take some test readings on higher gravity ales and any lager. One advantage to using kegs is the beer will continue to ferment and condition in the keg. You can also change the carbonation levels in the keg after you have tasted the beer.

I use a turkey baster

One note: beer from the fermenter will have CO2 dissolved and should be degassed for an accurate reading.

broadbill said:

Read the OP....they specifically asked if/how they should take multiple hydrometer readings DURING fermentation. If its still fermenting, then I guarantee the gravity will be different from one day to the next.

Once fermentation is done, and giving it extra time on top (which you should do anyway)....one reading before bottling is enough. If you want...take two readings...I've never seen a drop in gravity at this point in the game so I don't bother.

Click to expand...

What the OP said and what they probably meant are two different things. There's no real need to take gravity readings "during" fermentation with most beers. I concider it fermenting until it's bottled or kegged. So, checking for FG would be multiple times during fermentation if you ask me.

Either way, there's no "for sure" way to tell whether fermentation is actually done unless you do two gravity readings a few days apart. You may not have seen beers take more than two to three weeks, but it's possible. I've had it happen a few times with slower yeast. When you end up with a bottle bomb because you didn't check it a second time, you'll understand why we do it.

To each his own, but I wouldn't suggest habits like these to a new brewer. They should learn things the right way and then make decisions on their own.