10 Reasons Your Wine Fermentation Won't Start - Checklist

It's autumn and this is the time of year when our customers are making wine from garden grapes or country wines. More contact us than usual at this time of year with fermentation questions. Often it is that they are struggling to get the fermentation to begin.

There could be at least 10 reasons why your fermentation won't begin, and I've put them together here as a checklist.

Of course it's hard to tell what's going on in your kitchen from my place. But if you have sterile equipment, quality ingredients and live yeast, there should be no such thing as a fermentation that won't start. There will be a reason why your brew is seemingly refusing to get going, and it's your job to find it.

No Visible Sign of Fermentation

I have put together this 10 point checklist for when your wine appears not to have fermented from the start. So you have followed the wine recipe to the letter, but there is no sign of fermentation. When I say 'no sign', I mean that there is no air bubbling through the airlock even though you added the yeast (say) a few days ago. 

Incidentally, if you are making a kit, then follow the instructions provided to the letter rather than going off-piste with what I talk about here. The only reasons a kit won't start are likely to be dead yeast (which is exceedingly rare in a wine kit which is in date), or too cold a temperature to allow fermentation to begin (much more likely).

You may have Googled and found this post, or you've contacted us asking for advice and I've sent you here. So on with the checklist...

 

Wine Fermentation Won't Start - Checklist

1. If you added Campden Tablets to your wine, did you leave it for 24 hours before adding the yeast?

Your recipe may have told you to add campden to your wine ingredients. It should also have said you must leave it for a further 24 hours before adding yeast. 

Campden Tablets are designed to kill any bacteria and/or yeasts in your fruit, vegetables, or whatever hedgerow goodies you are using. This is because unknown bacteria and spores can spoil your wine. The idea is that you sterilise the fruit/veg juice before adding your yeast of choice. That means your fermentation should be predictable as the only yeast in your wine will be the one you added, with nothing else in there to spoil it.

Campden tablets kill everything, including yeast. Hence you must leave the brew for at least 24 hours after adding campden tablets before adding your yeast. That means the Campden has had time to do its job, leaving none remaining by the time you add the yeast. 

If you didn't leave the Campden Tablets in your wine for long enough for those gases to disappear before adding your yeast, you may have killed it. 

Solution: add more yeast, though be careful if there is likely to be a lot of sediment as a result of doing this (see point 9).

2. If you added Campden Tablets to your wine, did you leave the vessel open to the air for 24 hours before you added your yeast?

If your recipe told you to add campden tablets to the mix, it should also have said to leave the vessel open to the air for that 24 hours.

When you add sulphites like Campden Tablets, they start working away killing bacteria and moulds. They then dissipate into the air as a gas. You are usually advised to loosely cover the vessel with a clean tea towel/similar for that first 24 hours. This prevents fruit flies and dust getting in whilst allowing those gases to get out.

If you seal the unit when you add the Campden Tablets, the gases can't escape. This means that when you go on to add yeast 24 hours later, the gases will still be present. Those gases will either kill the yeast completely or partially kill it which may lead to a very slow start to your fermentation.

Solution: add more yeast, though be careful if there is likely to be a lot of sediment as a result of doing this (see point 9).

3. Are the conditions warm enough for fermentation to start?

You may have been happily making wine through the summer months, and now it's autumn. Whilst the days are still warm'ish, what you may not have noticed is that the temperature has dropped sufficiently, particularly at night, to prevent the yeast from starting. So if you've been brewing in your shed all summer, you may need to brew somewhere a bit warmer once the days start drawing in.

If you have used a yeast sachet that gives temperature guidance on it, check what it says. Many do give ranges and/or ideal temperatures, and these can vary quite a lot. Here are examples of the temperatures some yeasts need to work:

Lalvin All Purpose Yeast K1-V111610-35°C (50-95°F)

Lalvin Sparkling Wine & Champagne Yeast EC-1118 - 10-30°C (50-86°F)

Gervin GV9 White Wine Yeast - ferments down to 10°C.

If your yeast doesn't give any guidance, most yeasts should definitely work between a range of 21-24°C. And anything under 10°C means most yeasts will struggle to get going and/or continue fermenting. In most cases, too low a temperature is the reason fermentations don't start. Increasing the temperature is often enough to get it going.

Solution: move your vessel nearer to a heat source, such as a radiator or woodburner. Don't move it too close, because extreme heat can also kill your yeast. Once it starts, you can move it somewhere more convenient. Keep an eye on it, in case it stops again. If it does, you'll know your chosen position is definitely too cold.

4. Did you start your yeast according to the instructions?

Modern yeasts are very simple to use and most of them can be sprinkled on the surface of the liquid and they start working.  Occasionally you will find yeasts that need to be re-hydrated in warm water for a few minutes before using. If you don't do that, they often work anyway. But they might not. Lalvin EC-1118 is an example of this kind of yeast.

Solution: add more yeast prepared according to the instructions, though try to avoid too much yeast in your sediment (see point 9).

5. Has your yeast sunk to the bottom before it got going?

We advise customers to avoid continuously opening their brewing vessel once yeast has been added, because of the risk of contamination. However if your yeast hasn't moved around in a while, it may need a little encouragement. This may well be the case if it was cold when you mixed it and now, even though the liquid is warmer, the yeast is sitting on the bottom. Sometimes just getting it back in suspension can get it going.

Solution: swirl the demijohn around so the yeast goes back into suspension. If the brew is in a bucket, lift the lid and stir the mix with a sterilised plastic spoon, then quickly replace the lid again. 

6. Is air escaping from the vessel some other way?

Generally you know your fermentation is going because air is moving through the airlock. But just because it isn't, that doesn't mean fermentation hasn't started.

Take a good look at the liquid surface. If it's in a demijohn, can you see little particles moving around? If it's in a bucket, can you see small bubbles forming on the surface?

Not all fermentations are created equal, so it may just be very slow getting going. Or it could be that the lid of your bucket is not fitted securely, or the bung in your demijohn is allowing air to escape.

Solution: if you are fermenting in a bucket, make sure the lid is securely fastened so there is no air escaping there, and the airlock is firmly in the grommet so there is no air escaping there either. If you are fermenting in a demijohn, ensure the airlock is firmly pushed into the bung and the bung is pushed firmly into the neck of the demijohn. 

7. Is your yeast alive?

Sometimes, just as out-of-date yeast might still work, so in-date yeast may not. So check the use-by date on your yeast. If it's in-date and you want to double check that the yeast is alive, you can do that using these instructions https://www.almostoffgrid.com/blogs/almost-off-grid/homebrew-tips-is-it-ok-to-use-expired-yeast.

Out of date yeast

Solution: if you decide the yeast is dead, add fresh yeast. Though be careful if there is likely to be a lot of sediment as a result of doing this (see point 9).

8. Did you fit an airlock too quickly?

Most country wine recipes advise you to mix the recipe, add the yeast and leave the brew in the bucket covered with a loose fitting lid or tea towel. You then leave it like this for as little as 3 days, or as much as 10 days, usually stirring with a sterilised spoon daily, before sealing and adding an airlock. 

This is because you need your yeast to multiply, and yeast needs air to do that. So, whilst it sounds counter-intuitive to say 'it's so important to sterilise everything' whilst at the same time saying 'give it some air', that's exactly what I am saying. 

Once the yeast has reproduced itself hundreds of time, it will then start working on turning the sugar in to alcohol, and that needs to happen in a sealed vessel with an airlock. However if you seal and add an airlock before the yeast has really got going, the fermentation may never really get going at all.

This is most likely to be the problem if you could see evidence of fermentation before you fitted the airlock (such as bubbles on the surface), but it has now slowed down or stopped since you fitted the airlock.

Solution: open the lid again, or pour the wine back into a vessel with a wide neck (or the original bucket). Cover with a tea towel/cheese cloth or similar, with a rubber band around it as this will be very appealing to fruit flies at this point. Wait until you're certain the fermentation is working before you fit the airlock again.

9. Is it time to start again?

If there are any issues with your yeast at all, I have suggested you add more. In theory you cannot add too much yeast to a homebrew fermentation. If there is too much yeast for the sugar in your brew, the unused yeast will simply sink to the bottom along with other sediment and do nothing. And if your yeast is dead it will, again, just sink to the bottom.

But having a lot of yeasty sediment isn't ideal, if your wine is going to be sitting on it for a few months. It could affect the taste and/or and make the wine more difficult to clear. And in a handful of cases, if the yeast that has sunk to the bottom is actually alive, it might start fermenting again later. Cue: exploding bottles. No thanks.

Solution: if you've decided there's likely a yeast issue but adding more is going to mean lots of sediment, you could rack the wine out of the vessel into another sterile vessel leaving the old yeasty sediment behind. Then add fresh yeast and, in effect, start again. 

10. Is this too large a volume of liquid to get it going without help?

We sometimes start wine in a bucket and, rather than transferring into demijohns, we pop the lid on with an airlock. We can then make the whole brew in a large fermentation bucket from start to finish.

Pear wine in a bucket

However when you have a lot of liquid and it's cold, that means it takes much longer to get the liquid to the higher temperature needed to get a strong and consistent fermentation. You might want to consider transferring the large volume into smaller vessels (such as demijohns) so that you have more control over the temperature. Alternatively, you could remove about half a litre of the juice and add a packet of vigorous yeast (such as GV7 Restart or Lalvin EC-1118) to it in a sterile vessel. Stir well and place in a warm area. When you see it fermenting, pour it back into the original vessel. 

 

It may be that you're reading this simply out of interest. If you are reading it because you have a fermentation that won't start, we hope you find it helpful and you get your brew going very soon!

 

 

 

 

 

 

 

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