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carbonation is f*"king with my head !!!!!

jonnym_ch

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May 24, 2016
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hi all,

so i'm having some issues, and i'm not talking about my wife .... it's way more serious than that, it's the beer :)

i bottle my beers and add sugar prior to bottling using an online calculator to calculate the quantity of sugar to add. the beer is around 21?c (70?F) when bottled and that's taken into account when priming. the beers vary in abv from 4.5% for a pale to 6.5% for a saison. so far so vanilla.

recently however i've taken to brewing my pales, wheats, saisons and blanches drier than normal as i prefer them that way. this means mashing at the lower end of the scale. i generally tend to aim for between 1.004 and 1.008 for the fg (except for the saison which is lower). for carbonation i generally aim for 2.1 vols for pales going up to 2.5 vols for the other beers, but they have all turned out incredibly fizzy, way over what they should be.

so my question is, does the fg after fermentation have an effect on the carbonation ? and as a corollary of this, if fg is the factor that changes the carbonation, is there a way of adjusting my calculation to take this into account ?

it's really the only thing that has changed in my brewing so i can't help but think that it might be this.

appreciate any help you can provide !!!!

cheers,

jon
 
Some of the things to check out:

1) You mention Saisons.  A few of the more commonly used Saison yeasts are of the diastaticus variety.  Particularly WY3711 and potentially WLP045, WLP073, WLP099, WLP545, WLP566, WLP570, WLP590, WLP644, WLP740, and WLP885 according to the last article I have read.  (I have not brewed a Saison so I have not kept up with some of the more recent findings.)  As the yeast carries the ability to make extracellular glucoamylase, the residual sugars and dextrins in the beer may continue to be broken down and consumed by the yeast left in the bottles.  Contamination from this strain can easily affect other beers you brew.  StarSan sanitizer does an OK job at sanitizing bacteria but is not terribly effective on yeasts.  Iodine sanitizers have been shown to be more effective on killing residual yeasts.

2) Make sure that you are really at FG by checking your gravity reading at the end of fermentation over at least 3 days.  There should be no change from initial check to final check.  If you are truly at the FG for that beer, you will not see any difference due to a higher or lower FG in carbonation values.  If there were, the carbonation calculators would have that as an input for the amount of sugar required.

3) Measure and record your actual bottling volume and trub loss in the fermenter.  BeerSmith and other calculators use the net volume of beer in the calculation of sugar needed to carbonate your beer.  If you have less actual beer and more trub left in the carboy, then you are actually carbonating a lesser volume.  Since you are reporting a much higher carbonation level than your target, I cannot see this as your issue but it is better to know where you are at and plan on the correct volume.

4)  Don't rule out a sub-clinical infection of pediococcus or wild yeast.  These will act slowly and generally result in higher carbonation over time (maybe not as  slow as v.diastaticus).  One indication of this is to chill a bottle down to serving temperature, put it on the counter and then pop the top off.  If you see foam forming within a minute or two at the neck of the bottle, this is a sign of possible infection.  Decant the bottle onto a container you can cap (soda or water bottles work well), allow to warm to room temperature, now cap and shake the bottle to get the CO2 out -- it will take some time - releasing the gas as it comes out of the beer.  Once the beer is flat, check the gravity against the gravity of the beer you bottled.  If you have checked (2) above and the gravity is lower, then you most likely have a low grade infection.

I hope some of this helps. 
 
hi again oginme,
thanks for the info. yes, one of the batches definitely had a low grade infection (as per your note four). still tastes fine but you only want to open the bottle when it's really really cold :)

for point one, i'll definitely change my cleaning method for saisons from now on.
for point two, i am reasonably sure about the fg as i leave the beers a minimum of four weeks in primary before bottling checking fg after 2 weeks and confirming after 3 days (i don't bother with secondary as it's a hassle, risks infection and i am not bothered in the slightest about a little haze in my beer).
for point three, agree with you and all my carboys have the quantities in 1l increments on the side so, give or take a few mls i'm pretty sure that's not the case.

one other issue that might be in play is the carbonation system i use. i've built a shelving system in my boiler room that holds a constant at ~26?C (79-80?F) and i carbonate here for two weeks. could the high temp affect the way the yeast carbonate the sugar and any residual sugars in the beer ?

cheers for your time ... much appreciated !
jon
 
Additional thoughts:

Since you are fermenting to a pretty low FG, you have less body in the beer which can affect your mouthfeel.  The level of carbonation might be sensed to be higher due to the lack of body.  This may be some of the "fizzy" sensation you are experiencing.  I have fermented some of my wheat beers down to pretty low gravity readings and note that the carbonation seems to be a bit more effervescent on those beers.

What type of sugar are you using for carbonation?  Table sugar, sucrose, will produce a bit higher amount of carbonation than dextrose (corn sugar). 

Is there any reason you are using an on-line carbonation calculator versus using the one in BeerSmith? 

Your refermentation conditions are higher in temperature than I typically use, but it should only affect the rate of yeast activity.  In terms of consuming more of the sugars, the yeast will only consume so much before it flocks and precipitates from the beer.  Since you are fermenting down to a very low gravity, there should not be many sugars left in solution for the yeast to work on other than the sugars you add for carbonating. 

Wish I could be of more help.
 
Have had that issue in the past. I had a bad run, so I took all my equipment and bleach sanitized it for 24 hours. Bleach is a bit more complicated to use that other sanitizers, but i have found it to be much more effective in the long run than others I have tried (personal opinion) After letting all my hoses and plastics sit in the bleach for that time, I have had no issues, and I didn't have to go out and buy new equipment. I use all glass carboys and I only bottle, not keg.
Just throwing my 2 cents in there for you to consider.
 
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