Over Carbonation or Infection

[dachshund51288]

A little pretext.

I used to be an extract brewer and quickly began adding specialty grains. I brewed this way for a few years and was successful with my beers. About a year ago I switched to all grain brewing via the BiaB method and enjoyed the finished products I was getting. However, after a few BiaB batches I started noticing that all my batches started becoming over carbonated. It seemed like a few bottles at first (mainly the last few I would drink) but then the number began increasing with each batch. It never was bad enough that I had bottles exploding in my closet, but it got to the point where as soon as I would uncap I would have about 1 second to pour some into a glass or else the foam would overflow the top of the bottle. After this I found an online calculator and started diligently calculating how much priming sugar to add based on gallons of beer, beer style, and most importantly temperature. This helped reduce that immediate foam over upon opening, but I'm still getting over carbonated beers to the point that I get a really tall head and cannot pour the full pint.

I don't notice any rings around the top of my bottles that would indicate an infection. The sample I take on bottling day tastes really good (just not carbonated). The beer when over carbonated doesn't taste bad, but it doesn't taste the way it should but I attribute this to being overly fizzy, as after the head dies down it seems to taste mostly fine.

The only thing in my brewing/sanitation process that changed was the switch from extract w/ specialty grains to all grain BiaB. So I'm curious if I'm somehow getting an infection in every batch or if there is something else at play that I'm missing.

 

[ColoHox]

How are you measuring your priming sugar?

If you are using volume (cups), get a scale and start measuring the weight of the sugar instead.

 

[dachshund51288]

That was one of the initial changes I made. When I started using the online calculators for priming sugar I also started weighing it.

 

[ColoHox]

Just to get the simple stuff out of the way:

Your beers are at complete, total, final gravity before you bottle, right?

Does your FG regularly come out on the high side?

Not all infections will leave that ring in the neck of the bottle, and not all infections will cause off flavors, but many do cause gushers.

If it is a process issues, we can probably pinpoint it. If it truly is contamination, it will be difficult to find the source. Do you use plastic carboys or buckets as primary fermenters?

 

[dachshund51288]

Yep, I believe my beers are complete. I give my beers approximately 2 weeks in the primary and 2 weeks in the secondary. Usually the gravity reading after the primary and after the secondary are the same or different by about 0.001.

My FG regularly comes out at or below the predicted FG. So never a problem with unfermented sugars left over.

I'm not sure what a typical infected 'gusher' looks like, but I can say that I've never even come close to any of these: [ame]https://www.youtube.com/watch?v=jWDLK133Cjo[/ame]

Both my primary and secondary fermenters are are glass carboys. And I use the standard bottling bucket that came with my kit.

 

[hvjackson]

Couple other things to consider:

- If you are adding priming sugar to the individual bottles, switch to adding it to the bottling bucket first. Better control (and easier).
- Make sure the priming sugar is well mixed.
- Make sure you're using the same kind of sugar you did the priming calculations with. E.g. if you do your calculations with corn sugar and then instead add table sugar, you will overcarb.
- Make sure you use the actual volume of beer you're going to bottle. E.g. for a 5 gallon batch you may get 4.5 gallons in the bottling bucket.

 

[dachshund51288]

Priming sugar is always added to the bottom of the bucket. Then the beer is racked from the secondary into the bucket.

I always have used table sugar and always do my calculations with table sugar.

And yes, I do it based on the volume of beer I'll be bottling.

Aside from now calculating the amount of priming sugar to add, this is the exact same method I used to use before switching to BiaB brewing. Before, when I used to brew extract I would always use 5/8 c of table sugar for each batch and never had a problem.

 

[hvjackson]

Well you seem to have all the basics covered. If you want to go further down the rabbit hole I have some other things to think about:

- The "Beer temperature" setting in priming calculators is used to estimate how much CO2 is already dissolved in the beer. It's not necessarily obvious what temperature to use, but the Brewer's Friend priming calculator has a brief description of the significance and how to pick a value.

- Since switching to BIAB have you changed your recipes? Adding more protein (e.g. wheat) can increase head stability. That wouldn't directly change the carbonation but perhaps you've been overcarbing the whole time and by increasing head retention you've made it a messier problem. (For instance, American macro beers tend to be *highly* carbonated, but there's virtually zero head retention so it's not really a problem.)

 

[dachshund51288]

The beer temperature was the first thing I noticed when I started using the calculators, especially since it was winter time the ambient air temperature was in fact cooler. I don't have a fridge or freezer I ferment in, I do my best with the ambient temperature in my closet. So when the yeast is actively fermenting my fermometer is warmer than the temperature on the day I actually bottle.
Now, a liquid will hold more dissolved CO2 at a colder temperature than it will at a warmer temperature, so I always use the current fermometer temperature on bottling day (which is the lower reading than during primary fermentation).
If anything, I would presume that should result in under carbonated beers in the worst case scenario.

Regarding the extra protein. I don't add anything to my beer with the intent to increase head stability and the only time I use wheat is for wheat beers. Now, what I don't know is, since I'm using all grain via BiaB, am I automatically introducing more protein into my beer simply by mashing the grains? If so and if this is the issue, is there a way to reduce this?
When I'm done the mash process with my beer, I perform a mashout then remove the bag of grains. I then sparge the bag of grains with extra hot water. But I don't recirculate my wort through my used grains like typical non-BiaB all grain brewers would do. Another thing I've noticed since switching BiaB is the amount of trub in the bottom of my primary has increased. However, I give it plenty of time in the secondary and my beers always look clear.

Edit: most of my beers lately have looked like the 1st picture on this page http://www.brewersfriend.com/2009/06/01/over-priming-home-brew-bottle-bomb/
I open the bottle and have plenty of time to begin to pour it into a glass, but I usually can only pour about half in the glass before the head takes over the rest of the glass. Once the head subsides, I can typically easily pour the rest of my beer into my glass. If I just opened my beer and set it in the sink without pouring anything I'd probably end up with that 1st picture.

 

[dachshund51288]

Update from yesterday:

So I opened an IPA that was bottled 3 weeks ago last night. Appeared over carbonated based on cap hiss and head on beer. Was able to pour probably 3/4 of the beer into a pint glass, then could pour the rest once the head subsided.

Also opened a California Common bottled 3 months ago which which ended up looking like this example: http://3.bp.blogspot.com/_eziDJu6Xj9I/TJg1lGYsZNI/AAAAAAAACX8/FSXLtWMkHNU/s1600/beer+etc.+068.jpg

After the carbonation subsided, both beers tasted fine.

Finally, I bottled a my witbier. While my bottling bucket said I had about 4.5 gallons of beer, to reduce the amount of priming sugar I used this calculator for 4 gallons of beer at American Wheat Beer carbonation http://www.northernbrewer.com/learn/resources/priming-sugar-calculator/
Fingers crossed, we'll see how it turns out.