Homebrew Airlock Stopped Bubbling After 1, 2, or 3 Days (Is It Normal?)

As a first-time homebrewer, you may begin with the usual enthusiasm and excitement you’d get once you’re committed to starting a new hobby. Why has my homebrew stopped bubbling after one day? Or two or three days?

It is normal for the airlock to stop bubbling after 1, 2, or 3 days during the primary fermentation of beer. Yeast reproduces aggressively early in the fermentation process, creating lots of escaping air bubbles, which then slows significantly after a few days. Less yeast activity produces less carbon dioxide, leading to fewer bubbles over time.

As you continue to read, you’ll learn just how common and easy to understand how to fix homebrew that has ceased to bubble after one to three days.

Why has my homebrew stopped bubbling?

Of course, you know bubbling is an excellent visible sign your brew is fermenting healthily, yet it is safe to tell you that it isn’t the best way to identify whether your brew has completed the fermentation process.

I’ll break down the fermentation timeline for you (lagers and ales).

*Note* Understanding the fermentation timeline means you should also know what is happening during the fermentation process.

That includes knowing what yeast is doing during brew fermentation. Yeast is consuming the wort sugars and turning that sugar into carbon dioxide (CO2), ethanol, flavor compounds, and yeast cells.

When ale fermentation stops bubbling

Lag phase: three to fifteen hours after pitching yeast.

Once the yeast is pitched to beer, they begin a process called acclimation to the environment known as the lag phase. During this phase, the least behind to uptake minerals and amino acids from wort. Brewers will not see visible activity (bubbling) during this phase.

Exponential growth phase: one to four days.

During this phase, yeast comes out of the lag phase, and it begins to consume the sugars in the solution. Thus, carbon dioxide (CO2) is produced, which then begins to dissipate through the airlock. This process will then start to create a surface layer of foam on the beer. The cell count increases immensely, and ethanol and flavor compounds are produced. Airlocks begin to bubble like crazy during the growth phase. This will be the phase where the beer will be of high activity.

After the exponential growth phase of ale yeast has completed in about 4 days, it is likely that the airlock will stop bubbling.

The stationary phase of yeast growth: three to ten days.

This phase is where beer has matured, and the yeast has slowed down in activity. This phase is also called the conditioning phase.

When lager fermentation stops bubbling

Primary fermentation: one to twenty days.

The starter and wort should be chilled and remain chilled to the same temperature, and pitch the yeast. Lagers must ferment in cold temperatures (between 48° F and 55° F). The temperature depends on the strain of yeast.

After the exponential growth phase of ale yeast has completed in about 4 days, it is likely that the airlock will stop bubbling.

Diacetyl rest: twenty to twenty-three days.

During this phase, your wort will have fermented into beer. The temperature is increased to 65° F. Lager yeasts take approximately three weeks to ferment the sugars into alcohol fully. During this phase, a compound called Diacetyl is produced, which creates a particular butterscotch candy flavor.

Lagering: twenty-four to fifty days.

The temperature should be slowly lowered from 60° F to low 40s or upper 30s. The temperature should stay at the new temperature for a few more weeks. Lowering the temperature one to two degrees per day will allow the fermentation of the yeast to slow and turn into lager.

How long should my homebrew bubble?

As mentioned earlier, the airlock isn’t always the best way to determine fermentation activity (bubbles), so just because you didn’t see bubbles or not doesn’t mean it isn’t fermenting. The best option is to open the lid and observe.

Usually, within a 24 – 36 hour timeframe, carbon dioxide begins to bubble through the airlock. That is only if everything is functioning properly and if the fermenter is closed/sealed correctly.

Once active fermentation has started, your airlock should bubble aggressively for 1-4 days and begin to slow after that.

Fermentation can take approximately three days to begin to ferment if you decide to use fast active yeast and the temperature is of proper setting. In cold temperatures, fermentation can take up to seven to fourteen days or longer with larger beers. 

What do I do if my airlock isn’t bubbling?

If you notice your airlock not bubbling, there are a few possible reasons:

  • Active fermentation has not yet started
  • The yeast were not healthy enough to begin fermentation
  • Your wort was too cold or hot when you pitched yeast
  • The fermentation vessel is not sealed properly
  • Active fermentation is already complete.

If you aren’t sure that your fermentation has started properly and you are worried about what to do, I’ve created a resource to help you diagnose a stalled or slow fermentation.

How to make sure homebrew is still fermenting

There are a few ways to determine whether the fermentation process is active. This involves observing the following signs:

  • See if bubbles are escaping from the airlock.
  • Swirling particles inside the beer.
  • A yeast cake (krausen) forming on top of the beer.
  • Turn forming on the bottom of the fermenting vessel.

When observing the fermentation process, it is essential to take note of the duration of the process from start to finish. This is in case the obvious or visible signs aren’t present.

How do I know if fermentation is complete?

As a first time home brewer, you know one of the most important questions that arise is how do you know if the fermentation process is finished?

This is a great question and simple to answer.

You will know when to bottle your brew once you have read your hydrometer. You should read your hydrometer every one to two days. Once you see a reading that hasn’t changed, then your fermentation process is complete.

Can you let homebrew ferment for too long?

There is such a thing as too long of fermentation, specifically In the primary fermentation process. The length of the fermentation process is relatively short in the immediate fermentation process, so it is best to stick with a three-week time frame.