Beer temperature in relation to priming

[InspectorJon]

I bottle condition my beer. The last two batches were over carbed. They produced an excessive amount of foam when poured and would foam out of the bottle if it sat more than a few seconds after uncapping. I have done some reading and even asked here about what temperature to put into the priming calculator when it asks what temperature the beer is. The great majority of opinion seems to be to use the highest temperature the beer has achieved after it is finished fermenting. I also remember reading in a thread about suck back during cold crashing that the beer reabsorbs gas when it cools. With these two batches I used a mylar balloon to prevent O2 entering the fermenter and cold crashed into the mid 30s prior to bottling. This keeps the beer in a pretty pure CO environment. This is a pretty recent process change I have undertaken (balloon combined with cold crash). I suspect that the beer has reabsorbed CO which accounts for the over carbonation. Thoughts?

Other possibilities I think of are:

• I was got in a hurry and bottled before the beer was done, but I don't think so. I had consistent hydrometer readings for at least two days.
• The yeast was lazy and restarted later? Same yeast for both.
• Hop creep? I did a pretty heavy Mosaic dry hop on one but I did not dry the stout and it had the same symptoms.
• Infection? Maybe, but two separate batches and neither was over carbed enough to produce geysers.

 

[Spundit]

Any chance you got a lot of hop material in the bottles? IME this can give a lot of nucleation points for the CO2 and cause some gushers.

 

[marc1]

Hmmm... what kind of pressure does a balloon put on the headspace? If you have a large balloon with an excess of CO2 able to go into the beer, and then drop the temp to low 30s, maybe you are getting some.
If the balloon creates a few PSI, this may be the cause. If not, then no. I don't think mylar balloons are as pressurized as the regular ones, are they?

 

[sibelman]

Hop creep and/or the nucleation @Spundit mentions are certainly credible theories, but... your foaming seems most likely caused by infection. Though your list of possibilities is solid, I'm imagining you've generally been successful at assessing the completeness of fermentation. No math for this, but the cold-crash balloon doesn't intuitively seem like it would add enough CO2 to explain the foaming you described.

Carbonation issues can be SO frustrating! Best of luck.

 

[MaxStout]

You mentioned the last 2 batches over-carbed. I'm assuming every bottle in those batches was over-carbed, is that correct?

If so, we can rule out individual bottles having contamination. In which case, I'd go with either the nucleation issue, or a batch infection. Infections are so insidious, it can be as simple as microbes in the voids of tubing, connectors, drain valves, etc.

OTOH, if you are only finding some of the bottles being over-carbed, it may be those bottles.

 

[InspectorJon]

This happened to all the bottles but the smaller 12 oz bottles were more severely affected than the half liter ones. Nucleation makes sense for the Mosaic SMaSH pale ale with a heavy dry hop but the stout dropped pretty clear before bottling. The mylar balloon does not provide any head pressure as there is also an airlock, it just keeps a relatively pure CO environment. This is what I am trying to puzzle through - does the beer take any CO back into solution simply by cooling off. The priming calculators give some pretty different results when you change the temperature between 35 degrees and 72 degrees. The beer fermented in the mid 60s but did get did get that warm at the end. But then it also sat around 35 in a CO environment for a couple days before bottling.

I really don't want this to be an infection. I made the stout as a second runnings, smaller beer along with an Imperial Stout. Both were fermented at the same time with the same yeast. The Imperial Stout is great with no issues. They were both made with the yeast cake from the Mosaic SMaSH. The big stout sat in secondary and was bottled later and I did not open any until recently. It's fine.

 

[hamachi]

I'm assuming that the mylar balloon of CO2 effectively corresponds to force-carbonating at atmospheric pressure -- i.e., zero excess pressure. If you look at the lowest pressure column (1 PSI) in the carbonation table at Force Carbonation Chart - Kegerators.com , the solubility of CO2 at 35 degrees is 1.6 volumes, compared to maybe 0.8 volumes at 72 degrees (extrapolating, because the table only goes to 65 degrees).

So I guess the question is whether a carbonation level of 0.8 volumes more than what you expected could explain the gushers you see.

What was your target carbonation level?

 

[marc1]

I'm assuming that the mylar balloon of CO2 effectively corresponds to force-carbonating at atmospheric pressure -- i.e., zero excess pressure. If you look at the lowest pressure column (1 PSI) in the carbonation table at Force Carbonation Chart - Kegerators.com , the solubility of CO2 at 35 degrees is 1.6 volumes, compared to maybe 0.8 volumes at 72 degrees (extrapolating, because the table only goes to 65 degrees).

So I guess the question is whether a carbonation level of 0.8 volumes more than what you expected could explain the gushers you see.

What was your target carbonation level?

My understanding of non-normal cases like this is a little weak, but wouldn't you need the actual 0.8 volumes of CO2 to get it into solution at that temp? So if it's a 5 gallon batch, the balloon would have to lose 0.8 * 5 gallons = 4 gallons of volume from when it was at 72 degrees?

 

[DuncB]

Lots of credible suggestions. I'm wondering how much priming sugar was used?
Are you sure that fermentation was finished before bottling and priming.

Did you use a yeast that can slowly munch it's way thru big sugars ? I certainly had this issue when using windsor ale yeast and every bottle had to be nearly frozen and then poured promptly into a jug and allowed to warm before decanting into a glass.

 

[InspectorJon]

Thanks for thinking about this with me guys.

Target level was 2.4 volumes. The beer in the fermenter was 3.75 gallons. The balloon was full to start and pretty flat when done. I'm not sure how much volume the balloon has. I would guess maybe 2 gallons.

The yeast is a bit of an unknown factor. I propped it up from bottle dregs from Yellow Rose, an IPA out of Lone Pint Brewery in Magnolia TX. It is a house yeast that is reported to originate on the West Coast but they won't disclose much. It has more flavor character than the Chico strains. The brewer told me it likes 65-70 degrees. I have used it for a few years and not had this issue before. I fermented it a 64 this time but let it rise to 72.

I primed individual bottles with 1/2 tsp cane sugar for the 12 oz bottles. That has worked well in the past when bottling warm beer.

I measured gravity 2 days apart with no difference. Careful to measure at 60 degrees each time, measured with a digital thermometer.

 

[DuncB]

Well using the priming calculator on brewers friend

Suggests 3.75 us gall at 72 fahrenheit would have 0.81 vols co2 absorbed and to prime with 3.2 oz for that whole beer volume.

Cold crash it to 40 fahr and as you had an only co2 atmosphere due to balloon suggests that you have 1.46 vols dissolved and that you would need only 1.9 oz sugar for that volume.

Half a teaspoon of sugar weighs 2 g apparently, so you put 2g in each 12oz bottle. So 3.75 gall convert to oz divide by 12 and multiply by 2 and then convert that to oz and you will have an idea of your priming rate that you used.

I'm metric so you do the maths.

I suspect you over primed with the extra dissolved vols in your changed practice.

 

[Vale71]

Initial suckback is just gas contraction in the headspace (assuming relatively fast chilling performance) and provides no extra carbonation. CO2 does go into solution eventually but this takes time (the more so the colder the beer is) and is still limited by the available amount of CO2 which, unless you leave an inordinate amount of headspace in the fermenter, is relatively small and won't cause much of an increase in carbonation.

I'm afraid the simplest explanations are the most likely ones. You either bottled prematurely with residual fermentable extract available or you have a primary infection that you now need to try and eradicate from your equipment.

 

[Vale71]

My understanding of non-normal cases like this is a little weak, but wouldn't you need the actual 0.8 volumes of CO2 to get it into solution at that temp? So if it's a 5 gallon batch, the balloon would have to lose 0.8 * 5 gallons = 4 gallons of volume from when it was at 72 degrees?

That is correct. Considering that CO2 like any other gas also contracts as it cools you'd end up needing even more than 4 gallons of CO2 at room temp. This means that if you keep your fermenter chilled for long enough it will eventually start pulling in air through the airlock which will mix with CO2 until equilibrium is reached. Unless, of course, your balloon does hold 4+ gallons of CO2.