Quick answer
- No bubbles in the airlock does not mean nothing is happening. Check the hydrometer.
- If the S.G. is falling, the wine is fermenting, bubbles or not.
- If the S.G. stops falling above 0.995, check the temperature first (20 to 25 °C / 68 to 77 °F), then the yeast and nutrients.
It is the most common worry with a new batch: “My airlock isn’t bubbling.” We have made two kits side by side, where one bubbled so hard it oozed out around the stopper while the other barely made a bubble. Both turned out fine.
Step 1: Check the Hydrometer, Not the Airlock
Take a reading with your hydrometer and compare it with your starting reading.
- The S.G. is falling: your wine is fermenting. A lid that doesn’t seal perfectly lets the gas escape around the edge instead of through the airlock. Leave it alone.
- The S.G. hasn’t moved after 48 hours: fermentation may not have started.
- The S.G. stopped well above 0.995 and stays there for several days: the fermentation is stuck.
See How to Use a Hydrometer for Winemaking.
Common Causes and Fixes
Too Cold
Yeast works best within a narrow range. Wine kits like 20 to 25 °C (68 to 77 °F). Below about 20 °C, fermentation may be slow or may not start. Fermenting yeast makes its own heat, so once a warm enough room gets it going, it usually keeps going. Move the pail somewhere warmer, keep it off a cold floor, or wrap the fermenter with an adjustable brew warming belt. A stick-on thermometer placed halfway up the fermenter makes temperature easy to check.
Too Hot
Above 30 °C (86 °F), the heat can kill yeast. If that happens, cool the must back into range and add fresh wine yeast.
Weak or Old Yeast
If the temperature is right and nothing happens within 48 hours, the yeast may be old or damaged. Sprinkle a fresh packet of wine yeast on top.
Low on Nutrients
Yeast nutrient gives yeast the minerals and vitamins it needs to grow. It helps start slow fermentations and restart stuck ones. Use only the recommended amount. Too much can leave a bitter, salty taste. It may also foam up if added to wine that is already fermenting, so add it slowly.
What Not to Do
- Don’t move to the next step because the calendar says so. Wait for the hydrometer.
- Don’t add the stabilizers (metabisulphite and sorbate) until fermentation is finished. They stop the yeast.
- Don’t leave the wine uncovered. Air lets in vinegar bacteria, and once wine turns to vinegar it can’t be saved.
Frequently Asked Questions
How long before a wine kit starts fermenting?
You will usually see activity within 24 hours, but it can take up to 48 hours. Check the S.G. to be sure.
Is it normal for the airlock to stop bubbling after a week?
Yes. Most fermentation happens in the first 5 to 7 days. After that, it slows down a lot.
Can I restart a stuck fermentation?
Usually, yes. Warm the wine to 20 to 25 °C, stir gently, add yeast nutrient, and if needed, add fresh wine yeast.
Keep Reading
- How to Make Wine From a Kit: Step-by-Step Timeline
- Primary vs Secondary Fermenter: Pails, Carboys and Airlocks
Need a hand with your batch? Call us toll-free at 1-877-668-6160 (Monday to Friday, 8:00 a.m. to 3:00 p.m. Eastern) or send us a message.
This guide is adapted from the ABC Crafted Series booklet Wine From Kits: What the Instructions Don’t Always Tell You. Always follow the instructions that come with your kit.