How to restart a stuck fermentation

Ollie wrote to us to say the following:

I have just started my very first batch of cider, picked and pressed myself.
My question is, I did not use a fermenting bucket – instead I put the juice, yeast nutrient and yeast into a demijohn with an airlock.
The first few days I had lots of bubbles, but for the last three days nothing has happened, I read that there should be a steady ‘blip’ of bubbles, one every minute or so for a week or two.
Any advice would be great.

Thank you



Hi Ollie and welcome to the fizzy, fruity and ocassionally headache inducing world of cidermaking.

We generally use a bucket or similar vessel at first because a good ferment will produce a heck of a lot of bubbles. The top of the bucket might look something like a kids bubble bath for a few days. If you start straight off in a demjohn you get tons of bubbles gunking up the top, pouring over and generally making a mess.

As you didn’t mention any of that I suspect or your fermentation never really got off the ground.  Either that, or your bung has an air leak (unlikely).

So how do you restart a ‘stuck’ fermentation?

I suspect your yeast, so  re-pitch with a fresh starter. Thats fancy talk for ‘throw in some more yeast’.

Fill a glass vessel with roughly 3/4 of a pint of water. Add 4 tablespoons of sugar and disolve. Get a fresh packet of yeast. Stir in the yeast and whisk thoroughly. Cover with cling film and leave in a nice warm spot for half an hour. The yeast should be vigourously working on the sugar by now and the top should have a good layer of bubbles.

Pitch the sugar/water/yeast mix into your demijohn.  Make sure you have plenty of newspaper underneath as there should be a mess for few days.Do not replace the airlock. Just stuff a loose wad of kitchen roll paper in the top to keep the flies out. The fermenting juice will be putting out enough CO2 for the first few days to keep everything clean anyway.

Once the mess has subsided, replace the paper bung with your airlock and watch it blip merrily for a couple of weeks.


Sometimes a phrase really resonates. The new phrase for me is “Once you go conical you won’t go back.”

And seriously this is probably true for everyone who switches from flat bottomed to conical fermentation vessels. (If you are someone who proves me wrong, I would love to hear from you.)

What is conical fermentation?

So what’s the big deal? Well have you ever toured a brewery? All those big shiny fermenters have something in common with each other. They all have an ice cream cone shaped bottom.

why is that good? Well there are two huge reasons. One, it’s easier and two it produces a better brew.

when we brew in flat bottom vessels we have to siphon off from one vessel to another to take the brew off the “lees” that can spoil the flavour of our cider or beer.

With a conical fermenter you don’t need to do this. The dead yeast falls to the bottom of the cone where you can simply close a valve and unscrew and empty the lees leaving the brew happily working through its second fermentation. You don’t need a siphon, you don’t need a secondary fermentation vessel and there are no contamination concerns to keep you awake at night.

When you take the little pot of lees out of the system, you can use the yeast to start the next batch of brew.

so to sum up the benefits of conical fermenters:

You only need one so it’s cheaper

You only need one so it’s space saving

They are easy to use

They are less likely to lead so spoiled batches

For these reasons I think the phrase “On e you go conical you won’t go back” really is justified.

Joe Morgan wrote to ask if he had sufficient tannin in his recipe:

“I have a lovely old Bramley (4m tall) a small James Grieve (3-4 years) and a small Charles Ross (3 years).

My questions are…
Would I need to obtain some crab apples for tannin?
What is the best time to harvest each tree, early or late?

Well Joe, firstly your mix will be fine without additional apples, but would be even better with some apples with a high tannin content. Crab apples generally offer this, and they do seem to be everywhere, so just ask around. If you cannot find any you could (purists look away now) add some black teas or raisins to the brew. This will give you some of the flavour profile provided by crab apples. You might even consider adding oak chips.

As for the best time to harvest, I wait till the apples are falling naturally. Let the trees decide when its harvest time. If not all trees drop at the same time, that is no problem. After all, the fallen apples can sit for a week or two in a pile in the garden. This generally improves things in my opinion.

From: Lorraine
Subject: First stage juicing prior to adding yeast

Message Body:

I’m a complete beginner to this, so please forgive any obvious errors!

I’ve had my apples sitting in a 23 litre bucket for about 3 weeks now (with a few lemons) waiting for my larger 27 litre bucket to arrive so that I can transfer the liquid into the larger container – ready for the yeast fermentation process. It seems to have already gone through the stage where it bubbles over onto the floor, but this was without any addition of yeast!

I’m not sure if it still fit for drinking, since it’s been sitting there for so long – I’ve at least stirred at least once a day – but not sure about protocol regarding fermentation or simply going off! I must admit, it still smells ok, but the fermented/cidery smell has died down a little and changed slightly.

Would you start again with some fresher apples?

PS: It seems as if it’s already gone through a fermentation stage, since I’ve only cored them so they’re soaking with the skins on.

Your professional advice is humbly awaited

Hi Lorraine

Everything sounded Ok apart from a couple of things. Stirring every day is not such a brilliant idea as you can introduce airborne nasties that may turn your cider into vinegar. You mention smell and bubbles (good), but if you are really unsure taste the stuff and see if it has gone bad or not. Just a tiny sip will be enough to let you know.

But then my real concern is your last paragraph where you  say you have “only cored them so they are soaking with the skins on.”

Why core your apples? You don’t need to do that. The process is to crush apples, cores, skins and all to a pulp, then squeeze the pulp till the juice comes out and then just ferment the juice. The crushed Apple leftovers can be composted, fed to pigs or thrown away. We are only interested in the juice at this point.

Sorry I cannot be more helpful this time

Squeeze apples and the juice comes out. The instructions for that part of the process are clear enough. 2.5 kilos of apples should give a litre of juice. But what do you do if you want to stop there and bottle the fresh juice rather than turn it into alcoholic cider? Well here’s how. 

Firstly every utensil must be super clean as you will not be able to fall back on the antiseptic properties of alcohol and co2 that give cider makers some leeway when it comes to cleanliness. 

You might want to strain your juice through a few sheets of Muslin in order to get a really clear apple juice. 

Sterilise your containers and fill with juice. Now place the bottles upright in a big pan of water. We don’t want to Boil your apple juice, but we do want to keep it at a steady 77degrees centigrade or more for at least 30 minutes. This is pasteurisation folks. It the end of the process (make sure the tops and lids are also fully heated) seal up immediately when you remove them from the heat.

The apple juice should now store for up to 18 months. However, just a few surviving spores of yeast could be all that is required for fermentation to start and in a few weeks time you may be unlucky enough to have a bottle of juice explode with the force of a small atom bomb. I do hope this never happens to you. 

Got an email from ANDY MACAULEY who says: there does not appear to be any gas leaving the cider bucket (sealed with a bubble glass filter). What have I done wrong and how can I start the fermenting process or is it too late? the apple juice has been ‘brewing’ for about 2 weeks.

Well Andy, for the first couple of days after pitching in the yeast there is no need for an air lock. the juice should be fizzing away madly and you should see and hear the bubbles. It should look like champagne, fizzing away.
If this was happening but then when you added the airlock it stopped, then maybe the air seal was not tight and the CO2 escaped through a different route.

If there was no fermentation at the start and there has been no CO2 then there has been no fermentation.

The cause might be as simple as a dead batch of yeast. I would normally say pitch a new batch in and see what happens. However, you say that the juice has been standing around for a couple of weeks now. I would therefore personally dump it and start again, just to be ultra safe. God knows what might have grown in there during two weeks.