Hydrometer question

New to the forum and new to brewing. I don’t have a hydrometer yet, but will definitely get one for my next batch. My question is how often is too often to check the gravity? I’m only fermenting the small 1 gallon batch, so maybe the answer is don’t even bother. But I’m under the impression that taking the airlock off to do this would be a bad thing, introducing air to the fermenting beer, especially if I still have several days or even weeks to go. Is this OK to do regardless of batch size? I really would just like to know when it’s done, not necessarily abv. Thanks.

On a 1 gallon batch it’s a major portion of the beer. 4-6oz.

Starting gravity is not very important. If you use the extract given and have the volume, you should have the OG stated for the recipe.

The FG, more important to know that the yeast are done. But with the small volume you are working with, I would not be concerned about taking 2 readings post fermentation.

Let the beer sit for 2 weeks and bottle it. You will drink the 10 beers faster than they can become bottle bombs.

Get a refractometer, only takes a drop or two to get a reading.

There is that. :oops:

There are some good units on ebay for under $30. You do need to use a correction factor for when alcohol is present. You need to know the OG of the beer.


Thank you. OK, but what about opening the airlock several times? Is this bad for the beer?

Opening the air lock is not bad in and of itself. It does create another chance for infection. If your beer is done fermenting (no more bubbles in air lock, yeast is flocking out), it’s pretty safe from infection. Especially if you are only brewing 1 gal. You will probably drink in before any infection would have much of a chance to ruin your beer.

For the one gallon batch, I wouldn’t worry about checking the gravity. You can see the beer fermenting, so if it was an active fermentation (lots of foam), then let it sit for 2-3 weeks then bottle and you’ll be good. I normally check gravity once after a week to see where it’s at, then when I keg to see where it finished.

I typically check gravity twice. Once right after brewing, and once right before kegging. If the pre-kegging number isn’t as low as expected, I might warm it up and give it a few days and check again. But if its in the ballpark I don’t worry about it.

When you’re new to the process its natural to want to check on things, and as long as you sanitize well there’s minimal risk. As pointed out though, with a 1 gallon batch a sample is a sizeable percentage of all your beer. If you feel like you’re going to stick with the hobby I recommend moving on to 5 gallon batches soon.