A stuck fermentation is one of the most frustrating things that can happen when brewing a beer kit.
You pitch the yeast…
You wait a few days…
And nothing seems to be happening.
No bubbling.
No krausen.
No activity.
If you’re brewing a beer kit, you’re not alone. This happens all the time — especially for beginner brewers.
The good news?
A stuck fermentation is usually easy to fix.
First — Make Sure It’s Actually Stuck
Before doing anything, check your gravity.
Airlocks can be misleading. Sometimes fermentation is happening quietly without much visible activity.
If you’re unsure how to properly pitch yeast or what should happen during fermentation, check out my Guide to Pitching Yeast, where I walk through what to expect during fermentation.
Take two gravity readings:
- One now
- One in 24 hours
If gravity hasn’t changed, you likely have a stuck fermentation.
Why Coopers Beer Kits Stall
Here are the most common reasons:
1. Old Yeast
This is one of the biggest causes.
Many beer kits include yeast under the lid, and depending on storage conditions, that yeast may be:
- Older
- Weak
- Slow to start
As explained in my Best Beer Making Kits – Which to Use guide, most beginner kits include basic yeast packets, which can sometimes lead to slower or weaker fermentations.
2. Temperature Too Low
Ale yeast typically performs best around:
18–22°C (64–72°F)
If fermentation temperature drops below this range, yeast slows down significantly.
This is extremely common for beginner brewers.
3. Not Enough Fermentables
If you’re brewing with just the can of malt extract, fermentation may be weaker.
Many Coopers kits recommend:
- Brew enhancer
- Dry malt extract
- Dextrose
These help yeast ferment more efficiently.
How To Fix a Stuck Fermentation
Here’s the step-by-step process.
Step 1 — Warm the Fermenter
Move the fermenter to a warmer room.
Wait 24 hours.
This fixes many stalled fermentations.
Step 2 — Gently Swirl the Fermenter
Gently swirl to re-suspend yeast.
Do not shake aggressively.
Step 3 — Add Fresh Yeast
If nothing happens, pitch fresh yeast.
This is often the most effective solution.
If you’re new to this process, my Home Brewing Beginners Guide – 5 Steps to Good Beer explains the fermentation process in more detail.
Step 4 — Add Additional Fermentables (Optional)
If fermentation is still weak, you can:
- Add brew enhancer
- Add dry malt extract
- Add sugar
This gives yeast more food and helps restart fermentation.
Preventing Stuck Fermentation Next Time
To avoid stuck fermentation:
- Use fresh yeast
- Maintain proper temperature
- Use recommended fermentables
For more beginner-friendly guides, check out the full Beer Brewing Guides section.
Final Thoughts
Stuck fermentations happen to every brewer.
The key is:
- Check gravity
- Warm the fermenter
- Add fresh yeast if needed
Simple fixes… better beer.
Cheers,
Big Robb 🍺