View Full Version : oxidation when taking S.G. readings?

10-04-2010, 03:28 PM

I've been trying to find a thread that discusses about my question but to no avail.

I'm simply wondering if there is any risks of oxidation when taking S.G. readings because the airlock has to come off and therefore oxygen will get in the carboy or bucket.

It seems people take lots of S.G. readings but I'm afraid to do it too often as I know oxygen can be evil in the later stages of fermentation.

I realize that I should post my recipe and brewlog when I'm asking questions but this is a general question that I'm concerned with especially for after the 1/2 sugar break.


10-04-2010, 03:43 PM
So far, I haven't ha any oxidizing problems while taking an S.G. reading after the 1/2 sugar break. Of course, I thief off enough for a reading, then typically drink what I pulled off when it's a low reading, close to finishing. I can't speak to chemical answers, but it seems like as long as the yeast is still fermenting, they should keep pumping out CO2 that would expel ambient O2 that may have gotten in. I guess if you're really concerned about it, buy a little CO2 cartridge attachment, and blanket your mead with it after you take your readings.

Cheers, and welcome to GotMead! :)

Medsen Fey
10-04-2010, 03:51 PM
Welcome to GotMead Acadien!

As a general rule, meads are fairly resistant to oxidation, especially traditional meads. You can ferment meads (and wines for that matter) in open fermenters with no lid and not have a problem with oxidation during fermentation because the active yeast provide protection. You can open the container and take readings as often as you need to without the mead suffering damage.

With that said, after I have provided proper nutrition, pH management, and aeration early on, I generally stop taking readings until I think it is about done.


10-04-2010, 03:54 PM
There's not much risk, even for a while after fermentation finishes the mead is releasing a lot of CO2, so when you put that airlock back on it will refill the headspace with CO2 before anything bad can happen. Of course, once fermentation is finished you'll want to make sure there's as little headspace as possible and then avoid opening it too often, but as long as there's little headspace you'll be fine (it's all about headspace vs volume and surface area, a little bit is okay, even wine bottles have a small bubble of air in them).

10-04-2010, 10:17 PM
Thanks guys, very reassuring coming for you experts!