its amazing how much oxygen matters

My last few batches have been like this,

at about late day 1 or maybe day 2.... my airlock will be barely bubbling (1 bubble maybe every 10-20 seconds). So I crack the seal and open up the carboy up just for a second or so, briefly look inside, and then close it back up.

5 minutes later, the bubbling goes MAD!!! A bubble or two, every second!


Its amazing how reactive it is.

Hmmmm... I'm not so sure that the oxygen is actuall yused by the yeast to make CO2, which is what bubbles out of the airlock. O2 is used to make new yeasties, methinks.

Maybe you didn't seal it properly the first time... If you just opened it up to look inside, I'm not sure that too much oxygen would get in.

^+1

Sounds like the seal wasn't properly set the first time.

Correct me if I am wrong but as a newbie I've been doing a lot of reading.

If you just open the lid the air will get into the bucket but not into the wort itself. When you initially put the wort into the bucket you stir it to create oxygen bubbles in the wort. This is the oxygen that works with the wort + yeast to convert sugars into alcohol and produces co2. The oxygen thats inside the bucket will be pushed out by the newly created co2 therefore by opening the lid you are introducing very little oxygen that will be pushed out initially but in the long run the level of oxygen in the wort will be the same.

Nope, you're right. The yeast use dissolved oxygen. Some will get in to the head space and will actually dissolve into the wort, but not in a significant enough quantity and certainly not in a couple of minutes.

Another possible explanation is that the OP agitated the bucket slightly and the extra bubbling is CO2 coming out of solution.

I know the seal was fine..... but seriously, I've done this 4 batches in a row now. Opening the lid seems to give it that extra boost right as it starts to ferment.

What you're seeing as a perceived benefit could be a very real detriment. Once the lid is on the fermenter, leave it alone. You're only asking for infection.

how can you tell if it has an infection?

RDWHAHB. If it gets infected, you'll know. It'll look, smell, and taste absolutely awful.

The point is: quit opening the lid.

the yeast only need the oxygen during the reproductive phase..i think this may be a case of a little knowledge is dangerous.

read this for a starter on oxygen's role in yeast

Wyeast Laboratories : Home Enthusiasts : Brewers : Technical Information : Oxygenation

i think that you may have some "off-gassing" or something else happening...IF yeast were that responsive you would see a lot more efforts at an open style fermentation.

Thanks for the link - very interesting.

Yuri_Rage said:

RDWHAHB. If it gets infected, you'll know. It'll look, smell, and taste absolutely awful.

The point is: quit opening the lid.

Click to expand...

hmmm... well one of my batches did smell pretty rancid! I was doing a Wit with WLP400 and a hefe with WLP300. Fermented at about 67-69F. The Hefe took off like crazy once I opened the lid (even more than my Wit) but it started to smell bad after about 4 hours of bubbling strong......
Even from just the airlock it smelled bad.

Now I'm at Day 4 and the smell went away and bubbles nearly stopped....I checked the hydro and its already at 1012.

Don't worry about it! Fermentation usually smells like crap.

Talk about a spurious correlation! Stop looking at the beer or you'll ruin it.

Pivzavod said:

Correct me if I am wrong but as a newbie I've been doing a lot of reading.

If you just open the lid the air will get into the bucket but not into the wort itself. When you initially put the wort into the bucket you stir it to create oxygen bubbles in the wort. This is the oxygen that works with the wort + yeast to convert sugars into alcohol and produces co2. The oxygen thats inside the bucket will be pushed out by the newly created co2 therefore by opening the lid you are introducing very little oxygen that will be pushed out initially but in the long run the level of oxygen in the wort will be the same.

Click to expand...

Well, yeast use O2 to make new yeast and for aerobic respiration, but no alcohol is made.

Now, there's no creatures that I know of that are purely anaerobic, but I'm not familiar with the yeast we use in beer if it'll use O2 purely for reproduction and then goes anaerobic, even if there is O2 in the environment. But, I'm thinking as long as there is O2 in the environment, it's going to be using it and not making alcohol, just from the knowledge that aerobic respiration produces way more energy than anaerobic respiration.

And any air that goes into the bucket from a lid opening wouldn't diffuse into the beer in there except for maybe a millimeter down. Getting O2 into standing liquid is actually quite hard. It's one of the problems they have in bio reactions is getting O2 into liquids. Get a standing liquid too deep and the organisms are on the bottom, then they might not get any air!