To airlock or not to airlock.... or little bit of both?

[Aleman]

it's just when respiring aerobically they do so much more efficiently. . . .

Am I under a misconception believing that yeast does not readily produce alcohol aerobically?

Sorry but yes.
< :ugeek: On> You can provide yeast with say 12ppm of oxygen so it should respire aerobically, but if the concentration of glucose in the medium is above 4%, yeast will default to respiring anaerobically (producing Alcohol)

Most all malt beer worts have more than 4% glucose, and beer kits made with brewing sugar/glucose/dextrose certainly will have.

I am away from my text books, and it's been 20 years since I needed to remember these facts but IIRC 1 unit of glucose when utilised aerobically produces 32 ATP units (ATP is used for cell energy), when utilised anaerobically it only produces 6 ATP units (Possibly 8 I can't remember) so aerobic respiration produces at least 4 times more energy for cell metabolism than anaerobic respiration. . . unfortunately yeast evolution has prevented them from utilising this in a sugar rich environment. </ :ugeek: Off>

 

[pjbiker]

< :ugeek: On> You can provide yeast with say 12ppm of oxygen so it should respire aerobically, but if the concentration of glucose in the medium is above 4%, yeast will default to respiring anaerobically (producing Alcohol)

Most all malt beer worts have more than 4% glucose, and beer kits made with brewing sugar/glucose/dextrose certainly will have.

I am away from my text books, and it's been 20 years since I needed to remember these facts but IIRC 1 unit of glucose when utilised aerobically produces 32 ATP units (ATP is used for cell energy), when utilised anaerobically it only produces 6 ATP units (Possibly 8 I can't remember) so aerobic respiration produces at least 4 times more energy for cell metabolism than anaerobic respiration. . . unfortunately yeast evolution has prevented them from utilising this in a sugar rich environment. </ :ugeek: Off>

I wish I'd paid more attention in biochemistry lectures, or even read the textbooks I bought.

 

[evanvine]

< On> Thank you for straightening that out Tony, I had that silly idea about yeast for a very long time! < Off>

 

[shearclass]

I have some cheap kit with a plastic airlock that doesn't seem to do anything.

I was starting to wonder if it was important or necessary.

i can get a new airlock for peanuts, but I'm not sure what to do.

People keep talking about not letting Oxygen into the wort, but the instructions tell you to stir vigourously to introduce oxygen. Also, won't liftign the lid allow oxygen into the barrell?

If that is the case, how do you test the brew with a hydometer without getting oxygen into it. Very confused!

 

[shearclass]

I have bought a new airlock for a quid, and I have a dumb question.

It is by Youngs, called something daft like super ultra air lock, or super extra air lock. It came with no instructions. It has a plastic lid on top.

Dumb question - do i need to remove this tight fitting plastic cap from the air lock?? I assume I do?

Reading the thread I am considering not even using it. The only benefit i can see is that it gives an indication as to when fermentation has finished.

 

[pjbiker]

Best to take it off. Or don't bother using it.
Edit, listen to Moley and leave it on. don't really matter

 

[Moley]

People keep talking about not letting Oxygen into the wort, but the instructions tell you to stir vigourously to introduce oxygen. Also, won't lifting the lid allow oxygen into the barrell?

At the beginning, yeasties like oxygen to multiply and take over the bucket. As Aleman said, they spread more efficiently, so that's when you thrash the wort until your arm hurts. Later on is when you don't want to start splashing the beer about, but removing the lid to take a test sample isn't going to do any harm.

Dumb question - do i need to remove this tight fitting plastic cap from the air lock?? I assume I do?

No you don't, you leave it on, it doesn't fit tightly, there are three little ridges inside the lid which leave enough room for gas to get out but insufficient for even tiny flies to get in. If you don't believe me, try blowing through it.

 

[Vindiv8]

Although it does make putting the water in much easier if you remove it first :grin: But put it back on afterwards :thumb:

 

[shearclass]

Moley - thanks very much.

Upon closer inspection, the lid of my air lock has 8 small holes in it, so i'll leave it on as you recommend.

Vindiv8 - I don't know what you mean about taking it off to put water in? I'm not supposed to add water via the air lock am i?

 

[Moley]

It was a joke, he only meant the drop of water which goes into the airlock itself.

I have to admit that I don't actually know what you're asking about, the airlocks commonly available nowadays are the bubbler and the tubular ‘handy’ airlock as on this page. You would leave the cap on with either.

So what sort have you got, which has got 8 small holes? I've found a “Super Major” online but it just says “large cylindrical type” and there's no picture, so is it just a larger version of the ‘Handy’ ?

 

[shearclass]

Bit busy this morning but i'll post a picture on here later of it if you like, will do it this evening.

 

[shearclass]

Ummm how do I upload a picture?

 

[aneray]

Try this how to mate :thumb:

viewtopic.php?f=24&t=5745

 

[home brewer]

an interesting thread, one i'm preoccupied with currently, i understand that while we have a nice foamy head at primary then an open fv is ok, given that the releasing co2 will form the protective blanket over the beer. Once the head has subsided then i guess that's the time to get under an airlock, or would you leave the lid loose for anything up to a week ?
cheers
hb

 

[Rod L]

People keep talking about not letting Oxygen into the wort, but the instructions tell you to stir vigourously to introduce oxygen. Also, won't lifting the lid allow oxygen into the barrell?

At the beginning, yeasties like oxygen to multiply and take over the bucket. As Aleman said, they spread more efficiently, so that's when you thrash the wort until your arm hurts. Later on is when you don't want to start splashing the beer about, but removing the lid to take a test sample isn't going to do any harm.

Dumb question - do i need to remove this tight fitting plastic cap from the air lock?? I assume I do?

No you don't, you leave it on, it doesn't fit tightly, there are three little ridges inside the lid which leave enough room for gas to get out but insufficient for even tiny flies to get in. If you don't believe me, try blowing through it.

It sounds like a 3 peice airlock, take the cap off, fill it half way up with water and put it in your lid of your fv