Failed Carbonation. Why is it so?

[Chalkyt]

There have been a few recent posts about unexplained failed carbonation. I have just fallen victim to the same thing. Any thoughts as to why this can happen since I can't see any reason?

This 5 litre batch started on 5 June with a mix of Pomme de Neige (Fameuse), Cox's Orange Pippin and wild apples... my "best" blend. Brix was13.0, SG 1.052, pH 3.7 and TA 6.5 g/L with one campden tablet and a teaspoon of pectinase added. Three days later 1/4 tsp of DAP and 5g S04 was pitched dry (usually a very reliable approach). By 10 June a robust foam had developed which settled on 15 June so the Primary was transferred to a carboy under airlock. All looking normal for a good slightly sweet carbonated cider.

The cider was bottled on 30 June at 1.010 with one bottle fitted with a pressure gauge. By 4 July, pressure was 1 bar (15psi) so far, so good. But there it stayed! Temperature hovered around 15C, which is convenient because at that temperature one bar is approximately 1 volume of CO2.

Since then, there has been no change. I opened a bottle today in case the gauge was faulty. The cider was slightly spritzig... like 1 volume of CO2. Brix is 6.2 or SG 1.008, so a change of around 1.002 which indicates about one volume of carbonation and that is how it tastes. i.e all the numbers add up, so why has it stopped. The idea was to pasteurise at 2 volumes or 1.006 for a slightly sweet carbonated cider.

Crown caps were new, treated with Starsan and rinsed in previously boiled warm water. Bottles were rinsed, dishwasher washed at 65C and sanitised at 150C in the oven. All quite normal.

So, after going "gang-busters" for five days, any ideas why fermentation would suddenly stop. I will recover by decanting, add a starter, bottle and start again but am mystified.

 

[Bobby_M]

You didn't mention adding any more sugar for the bottling. Did you?

 

[Chalkyt]

No, I wanted to finish around 1.006. The original plan was to ferment down to 1.000 then add sugar back up to 1.010, but when I was checking fermentation progress it was at 1.010 and it seemed to be an opportunity to bottle and pasteurise "on the way down". And it seemed to work for a while.

At 1.010 there should be 20g/L of sugar. Fermenting down from 1.010 to around1.006 should consume 10 g/L of sugar, generating a bit over 2 volumes of CO2/L, and leaving 10g/L (1/4 tsp per glass) of sugar for a touch of sweetness.

The only other thought is that both Jolicoeur and Lea talk about limiting nutrients (i.e. YAN) to control fermentation. The bottled cider is very clear (little or no yeast floating around?), so to see if this is the problem, I have opened a "test bottle" and have a glass of the cider with a pinch of DAP added to see if fermentation starts up. I will monitor the glass and the bottled cider over the next few days to see if there is a change in SG/Brix. Insufficient YAN is the only thing I can think of. As I said above, the recovery might involve decanting, adding a starter, then bottling again.

 

[teddyearp]

First off, I think I've learned more from you, much more, but here'd my thoughts.

I make mine from store bought. SO4 has been iffy when it comes to bottle carbing. I've never tried bottle carbing without tossing about 3Tbsp of sugar to backsweeten and carb (from your size batch). If all else fails get some conditioning yeast I mean, especially if you're not going to use a back sweet.

'Course I usually go to 35 psi before I cold crash.

 

[Chalkyt]

Hmm! Your thoughts on S04 are interesting. I used the S04 because I am using up the "leftovers" (we are now well into winter and I have a bit of AS2 and M02 in the fridge the opened but sealed foil packs).

Today I washed the last of the windfalls (Pomme de Neige/Snow Apples, Red Delicious, and Wilds) in order to just toss everything into a "quaffer". I might do it with the remaining AS2 which I have found to be quite good and see if it behaves better than the S04 for conditioning. Yep, 35psi is in the right spot, about 2 volumes. For me when waterbath pasteurising, this keeps bottle pressure below 100psi at 65C

 

[teddyearp]

Ahh, yes. You're halfway across the globe from me, but more north-south than east-west IIRC.

I'm at about 1900 meters elevation in the southwest USA. So it gets maybe 80 degrees with a few days of 90's at most. Otherwise, in the winter, it gets cold and I usually have to put my brews in a warmer room, an inside grow tent make for a symbiotic relationship, hehe. But I only brew from store juice so . .

 

[Bobby_M]

Making predictions about the exact attenuation of a fermentation is not going to be 100% reliable. That's why letting it ferment out all the way and then adding the sugar back to generate the carbonation you want is more common. You don't need to predict anything. You just wait.

 

[teddyearp]

Making predictions about the exact attenuation of a fermentation is not going to be 100% reliable. That's why letting it ferment out all the way and then adding the sugar back to generate the carbonation you want is more common. You don't need to predict anything. You just wait.

Agreed.

 

[Chalkyt]

Yep, you are probably right. Looking back at a similar S04 batch about a month earlier, at 1.002 ( S04 will sometimes finish above 1.000) I added sugar to 1.008 and bottled on 6 June. Opening the "test bottle" on 24 June was JAR (Just About Right) carbonation and SG 1.004 ready for pasteurising.

It looks like a case of decant, add sugar and start again.

 

[teddyearp]

Yep, you are probably right. Looking back at a similar S04 batch about a month earlier, at 1.002 I added sugar to 1.008 and bottled on 6 June. I opened the "test bottle" on 24 June and it was JAR (Just About Right) carbonation and SG 1.004 ready for pasteurising.

Quick off topic. Does pasteurization get rid of that tiny bit of silt in the bottom of the bottle from this awesome natural way to carbonate our drink?

 

[Chalkyt]

No... IME it tends to form clumps which float around for a bit immediately after pasteurising. If you leave it for a while, they break up if you shake the bottle and settle back on the bottom as per normal. I suppose it is due to the pasteirisation heating process but also seems to depend on how clear the cider is to start. I only pasteurise to 65C, and as 60C is the "magic number" where pasteurisation starts, there isn't much room to move on lower temperature. It may also depend on temperature x time as some commercial operations use flash-pasteurising where the product is exposed to a higher temperature for a short time and the outcome is commercially acceptable... but that approach is well beyond my resources which comprise a large bucket, sous-vide heater and timer.

I generally don't tip the last bit of a bottle into the glass and find that the last cloudy bit tastes the same as the clear stuff, but aesthetically it may not be desirable,

 

[Chalkyt]

Just an update... Decanted and added 25g of sugar (5g/L) plus a starter in juice (1/2 teaspoon of SO4 with a pinch of DAP and 0.5 grams of sugar), then re-bottled. This took off almost straight away and today after six days, bottle pressure was 1.5bar (22psi) and still going.

After pasteurising today, it taste-tested as a semi-sweet carbonated cider.

Happy days!