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Why is there no bubbles in the airlock?

no bubbles, no fermentation?

If you're a new brewer, you might be pretty keen to see some bubbles in the airlock after you've made your first beer.

We can also imagine your concern when you check your beer the day after you've brewed and hear and see no bubbles. 

And you'll have asked yourself:


 Why is there not any bubbles in the airlock? 



That's a fair question to ask and there are often some simple answers which should arrest any concerns.

It could be that there was a leak that allows the CO2 to escape from the fermenter. To teach you to suck rotten eggs, those bubbles in the air lock are carbon dioxide gas, the bi-product of fermentation and so could easily escape of the fermenter is not properly sealed.

You may have not tightened the drum enough or possibly not screwed in the tap properly. It's a good idea to check this is the case before you worry too much about a lack of bubbles.

If you didn't see any signs of fermentation it could be that it's too cold to brew.


Is your batch of beer in a warm enough place? If you're brewing during summer months, it's probably not too cold and your beer will ferment just fine and the bubbles will share in your beer making joy. 

If you've left your beer in a cold place in the shed, then it may be too cold for fermentation to begin. If this is the base then you might want to consider moving your fermenter inside to a warmer place.

If you insist on keeping the fermenter in your man shed, you could consider wrapping it with blankets or old painting sheets like I do. 

This is a handy trick and will help to keep the chill off your homebrew. 

You've checked and you have no leaks so is no bubbles in the airlock really a sign of a lack of fermentation?


The first thing to bear in mind is that it can take at least 15 hours of your Earth time before the CO2 bubbles start gurgling through the airlock.

So don't go drowning your sorrows just yet if the bubbles haven't started. 

If you think that your beer hasn't started brewing there's some very easy problem solving you can try. 

Look for the scum


If you are using a glass fermenter you can look for a dark scum that rings around the water level mark. 

You can probably see it through the standard white fermenter drum as well. If the scum is sticking to the side, at the top of the water line, you can be pretty confident that fermentation is under way and your beer will be just fine!

You can also check for signs of foam. 

A nice foam at the top of the water line also indicates that fermentation is taking place. 

So I'm pretty sure fermentation has not occurred. What happened?


Give it 20 - 48 hours before you start to worry about a lack of bubbles or signs of fermentation. 

Then you may wish to consider other things that could have occurred. 

When you pitched the yeast, did you add it to a wort that was at the right temperature? If your wort was too hot and not cooled properly, your yeast may have died due to the heat. 

If you think you killed your yeast, you can always re pitch with another set. 

Was your yeast fresh? If you were using an old packet, the yeast may have lost its spark and not have enough viable units to begin fermenting. 

Did you rinse out the sanitiser? 


As an expert beer brewer, we KNOW you carefully sanitised the fermenter and all the equipment you used. But did you rinse if off it was the kind that needed it? If you cleaned with bleach, you need to rinse other wise the residue could have killed your yeast. 

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