Carbonation Issues

My boyfriend and I have been homebrewing for about 4 months now, using kits.  After much research (and overthinking on my boyfriend's part), he decided that we should cold crash our beers while in the secondary, using unflavored gelatin.  Our process is beer is in primary for 1-2 weeks (depending on brew), then we cold crash at the end of the secondary period.  We bring beer to approx. 32 degrees, add gelatin, then continue at 32 degrees for 3 days.  We bring beer back up to desired temp before bottling.  We have had great results on the clarity of the beers.  However, we have noticed some of our brews appear to be flat (even after proper bottle conditioning).  We have checked the lids and they all seem to be tight.  Is it possible that the cold crashing could be causing issues with carbonation.  Or any other guesses as to why we don't seem to have optimum carbonation.  Thanks!

One simple answer could be that you are serving the beer too cold. Pour a glass at room temp and see if it has more head. Many new brewers think that beer should be ice cold. Light Lagers and Pils are intended to be very cold but most "good beer" is best at temps between 45 and 55 depending on the style.

Dirty glassware could cause this too. Clean and "beer clean" are two different things.

The other issue could be that you are not using enough priming sugar. Bump it up a bit next time but, don't over do it.

If you are planning to stick with the hobby you should get into kegging. That will make things much more simple.

Thank you so much!  You could be correct about the beer being served too cold.  We have a mini-fridge in the basement that is awesome for can beer, but may not be useful for our homebrew.  The majority (and I mean 99%) of our beers have been properly carbonated.  We are just starting to drink the beers that we cold crashed and have had 2 or 3 that seemed flat.  We just wanted to nip the problem in the butt before we continue using the same process for future brews.

And as far as priming sugar, we just use the amount the kits come with.  Maybe it just isn't enough with the extra work we put our brew through.  We are wanting to get into making our own without use of kits, so that is good to know.

Again, thanks for your help!

When bottle conditioning, it is important to store your bottles for few weeks at the ideal temp range of the yeast you are using to get the fermentation going to carbonate your beer. After bottling always move to the warmest location in the house. Chill one down to "your" desired drinking temp and check to carbonation level. If you need more carbonation, a little more time at elevated temps will continue the carbonation process if there is any sugar left to ferment. You will learn to appreciate your home brew at higher serving temps. You will notice how the flavors change as it warms. Enjoy your brew!

Yes. River is correct. I was assuming you let the bottles set in a warm place during bottle conditioning. If you did all that then it could just be the serving temp. Cold crashing has more to do with clarity than carbonation. Once you prime and bottle, get it to a warm place then chill it after a few weeks. Don't chill it until conditioning is done.

Well  I just had to check a few reference books,

The cold crashing does flocc out some of the yeast, but it is the gelatin that grabs the yeast and settles it out.
Yeast: The Comprehensive Guide to Beer Fermentation says 65-69 for carbonating. This makes perfect sense since it is in the recommended manufacturers ideal fermentation range for most beers. Too high a temp will kill off the yeast.

So you need to determine if you have enough yeast and or sugar in the bottles to complete the carbonation process. You need only 10-20 times less to carbonate than your original fermentation or only 1 million cells/ml for filtered beer up to 5 million cells/ml for high alcohol beers

I would move a couple of bottles to a warmer area to see if it improves. If time doesn't improve the carbonation you may have to add yeast at bottling.
If you have a good dusting of yeast on the bottom of the bottle, you may need more sugar.

RiverBrewer said:

Well  I just had to check a few reference books,

The cold crashing does flocc out some of the yeast, but it is the gelatin also grabs the yeast and settles it out.
Yeast: The Comprehensive Guide to Beer Fermentation says 65-69 for carbonating. This makes perfect sense since it is in the recommended manufacturers ideal fermentation range for most beers. Too high a temp will kill off the yeast.

So you need to determine if you have enough yeast and or sugar in the bottles to complete the carbonation process. You need only 10-20 times less to carbonate than your original fermentation or only 1 million cells/ml for filtered beer up to 5 million cells/ml for high alcohol beers

I would move a couple of bottles to a warmer area to see if it improves. If time doesn't improve the carbonation you may have to add yeast at bottling.
If you have a good dusting of yeast on the bottom of the bottle, you may need more sugar.

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to kill off the yeast you would have to raise the temp north of 140* although most of them would be gone after ~120*. sierra nevada and most other large breweries that bottle condition store bottles at or above 75*f during the conditioning phase. you are not after any yeast growth and the amounts of yeast character produced during this period is so low as to be negligable. will you get carbonation at 65 but it will be much much quicker at 75.

that said, it's possible that a good cold crash and geletine would remove enough yeast to make it uncertain and adding some (.5 packets dry) at bottling time will ensure solid carbonation.

A quick google yielded this answer from Mister Wizard at Brew Your Own magazine.

https://byo.com/cider/item/1655-would-fining-with-gelatin-have-an-adverse-effect-on-naturally-conditioned-beer

The gist of it is that the gelatin is likely not leaving enough yeast behind to do the job.  Adding some yeast when bottling should give the desired result.

We are in agreement which is a good thing. Without seeing the bottle sediment, it still the best explanation. Gelatin will be a part of the bottle sediment, too, which will be a problem for the yeast. I would try the bottle warming to see if there is any positive response. If there is nothing positive, Jen will know how to correct it! 

Thanks everyone!  I'm glad there's a consensus!
We do leave the bottled brew upstairs for approx. 2 weeks, sometimes longer.  Temp in our house ranges anywhere from 68 to 72 degrees, depending on who gets to the thermostat first!  We then move it to the basement for another 1 to 2 weeks before chilling to drinking temp.  Temp is around 64 at the moment. 
I did go ahead and purchase some extra priming sugar and dry yeast for bottling time, so I think we will definitely try that next go round!
Thanks again!

Another very simple solution that does not require any additional expense--just a bit of contrarian thought--is to not approach your racking from the fermenter to the bottling bucket quite so gingerly.

Yeah, yeah--it's drilled into our heads as fledgling homebrewers not to stir up the lees when we're racking from vessel to vessel, but this neglects the fact that yeast are our friends, and at least a few of them deserve entrance to the championship round. If you're kegging and force-carbing, well... so long, suckers. But if you're intending to bottle condition, feel free to kick up a bit of the settled yeast while racking into your bottling bucket. You'll make them happy that they are The Chosen Ones and they'll make you happy by giving you a delightful fizz in your properly-conditioned bottled beer. Kind of makes you wonder who's the symbiote, right?

(To be clear, I'm not advocating Hoovering up a cup of yeast sludge. A couple teaspoons, give or take, will suffice. These guys aren't dead--they're just resting--but they'll be happy to do their job and then glom onto the bottom of bottle when they're tuckered out.)

If your going to use a clairifier. Your better off using polyclar in the secondary and gelatin when bottling. I've have found  Irish Moss last 5 to 10 min from flame out , a good cold break, and let the wort settle for 10 to 15 min before transferring to my primary, a good cold crash,  eliminates the need for either one.

If you have some bottles in a batch that are well carbonated and others that are not it may be because you didn't stir your priming sugar into the batch well enough.  I had this issue with an Irish Red a few years ago. 
I tried a cold crash like you described on my last batch and am experiencing a carbonation problem in my keg!  I'm up to 20psi and it still won't carbonate. (???)

I'm up to 20psi and it still won't carbonate.

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I've discovered that when the keg is quite full then it takes a lot longer to carbonate. It needs some headroom. Don't worry. It will happen. Try drinking a glass or two. That should speed things up.