Bottle conditioning

[dcofth...@gmail.com]

I want to bottle condition 200 litres of cider in 500ml swing top bottles. The aim is to get a carbonation level of about 3.5 volumes of CO2. How much sugar, yeast and sulphites should I add to the 200 litres?  I plan to use a champagne yeast such as Lalvin  EC-118. Every time I work out the maths, I get a different answer depending on which guide I've just read. Experienced help needed! 

[terryc...@gmail.com]

These are my “experienced amateur” suggestions. I bottle and carbonate much smaller batches but you might be able to relate my experience to your volume. I generally go back to first-principles in order to understand the process rather than rely on tables, magic formulae etc to work out how much sugar per bottle.

As far as sugar is concerned, I add sugar (or unfermented juice) until the SG reflects the appropriate amount that will result in the C02 I want. The “rule of thumb” is two gravity points will ferment into one volume of C02. Assuming that your 3.5 volumes includes the residual C02 in the cider at bottling time (anything between 0.5 and 1 volume, depending on how long it has been sitting after fermentation… 0.8 volumes is a common guestimate), you will want enough sugar (SG) for 2.5 to 3 volumes of in-bottle C02 on top of the residual. It is this extra C02 that makes the fizz, not the residual.

Two references to help you with this are Andrew Lea’s Carbonation Table and Alex Simmons, Llanblethian Orchards Bottle Conditioned Cider Guide which I used to calculate how much C02 will come from the sugar, e.g. for a 500ml bottle, 2.5 volumes of C02 is 0.5L x 2.5 = 1.25L of C02. Using C02 = 1.977g/L and sugar ferments into 47% C02, each 500ml bottle needs 1.25L x 1.977g/L = 2.47g of C02/47%=5.26g of Sugar. This is 10.5g/L or about SG 1.005, surprise, surprise two gravity points per volume of C02! So just start bottling SG 1.005 cider and don't worry about adding sugar to bottles. This approach applies to any size bottles. 

There may well be enough residual yeast for conditioning to take place. I never need to add yeast, but I do generally bottle within a few months of complete fermentation. I have seen suggestions ranging from “a pinch” to ¼ of the original amount if there is any concern about yeast depletion. Others can probably comment on this with more authority than me.

As far as nutrients are concerned. Both Claude and Andrew have referred to their research suggesting around 50ppm of DAP per 0.010 of required SG drop, assuming that all nutrients have been consumed during fermentation (unlikely). The end of Claude’s book section 14.2 covers this. If bottling at SG1.010 (1.005 for carbonation then heat pasteurise at 1.005 to stop further fermentation to retain some sweetness), I will sometimes add 50ppm of DAP if using a high nutrient demand yeast like S04, just to ensure complete bottle conditioning.

Hope this helps… Good luck! 

[dcofth...@gmail.com]

Thank you Terry....I think that's a little bit clearer. I'll let you know how it goes.

[gareth chapman]

a rule of thumb that works fine for me is that 2.6g/l sugar will yield 0.6vols of co2. and 2.5g/l being equal to 1 point of SG drop so agreeing with the above that a 2 point drop equals 1 vol of co2.
My method which although it doesn't take account of the effect of the alcohol on the S.G works well enough. take the SG reading to determine the amount of residual sugar if any, then add extra sugar at the rate above. This would be for a well aged cider that has been racked with a pump so pretty much degassed. For a younger cider I might knock back the calculation by half a volume. Seems to work pretty consistently for me. I do add yeast and nutrient at the appropriate minimal rate for the amount of yeast and sugar to be fermented.

[James Fidell]

On 22/09/2025 02:28, terryc...@gmail.com wrote:

> If bottling at SG1.010 (1.005 for carbonation then heat pasteurise
> at 1.005 to stop further fermentation to retain some sweetness)

How do you determine when the SG is 1.005 once the cider is in the
bottle? Or have I misunderstood?

Thanks,
James

[terryc...@gmail.com]

Hi James

I probably should have explained the process a little better. The idea is to use pressure in the bottle (i.e. volumes of C02) as a proxy for determining how much sugar is consumed in generating the “in-bottle” C02. The remaining sugar is then available for sweetness. Pressure is the only thing that is measurable once the bottle is sealed. Getting the bottling SG right is key as this determines what mix of carbonation and residual sugar you will get 

You can use a flexible bottle “squeeze test”. But a test bottle with a pressure gauge is better (I have a Grolsch type bottle with a pressure gauge fitted to the flip-top… drill a hole through the flip-top then attach a small pressure gauge using whatever works, i.e. drill and tap the hole, epoxy, etc, etc.). I do a test bottle with every batch (and sometimes even open one of the batch bottles just to make sure. This is just a ploy to drink the test bottle… Yum!!!)

Roughly, 4 -5 g/L of sugar will ferment into 1 volume of C02, and in the temperature range where we normally bottle (15C-20C) 1 volume is about 1 bar or 15psi so the pressure is used as a proxy for volumes of C02 which in turn tells you how much sugar has been used, hence how much is left for sweetness. In practice there isn’t much difference between 8g/L and 12g/L residual sugar as they are both “sort of” like ½ teaspoon of sugar in a cup of coffee. So, the amount of carbonation is the key measure.

The calculations are not strictly linear as temperature, type of sugar (i.e. how much C02 it ferments into) etc come into play as well as how much residual C02 is already in the cider (a common “guestimate” is 0.8 volumes) and are based on Henry’s Law, but the easy way is to use Andrew Lea’s Carbonation Table to relate volumes to pressure. The amount of fizz is the amount of carbonation shown on the gauge, remembering that total target volume includes the residual C02 after fermentation that doesn’t contribute to fizz. i.e. a 2.5 volumes target = say 0.8 residual volumes plus 1.7 “gauge” volumes generated in the sealed bottle.

Anyhow this approach works well for me as I often hot waterbath pasteurise to produce a slightly sweet, carbonated cider. Cheers!

[James Fidell]

On 25/09/2025 07:44, terryc...@gmail.com wrote:

> I probably should have explained the process a little better. The idea
> is to use pressure in the bottle (i.e. volumes of C02) as a proxy for
> determining how much sugar is consumed in generating the “in-bottle”
> C02.

Thanks for the explanation, Terry. That's very helpful.

James