Newbie Carbonation Question

[Cultkid]

Hi All, I am pretty new, just working on my 8th batch of all-grain beer and I have a question about carbonation.

I generally batch carbonate my beer, which is to say I grab a cup of dextrose, boil it in another cup of water to sterilize/dissolve the sugar, and then put that in the bottom of my bottling bucket. I then rack from my secondary onto the sugar water, and when the bucket is full, I start bottling.

With the previous batches, they all bottle carbed up fine. I let them sit for 2-3 weeks generally speaking at aprox 23ºC ambient temperature. They've all come out great with a decent amount of carbonation without being overly soda-pop carbonated.

HOWEVER, I recently bottled 2 batches a couple of weeks ago. A milk oatmeal stout which I used 3/4 of a cup of sugar for a 6 gal. batch. It turned out perfect; but the other batch, a Rauchbier, didn't carbonate hardly at all! I used the same 3/4 of a cup of sugar for 6 gal. and it's basically flat... what did I do wrong, or why is my beer not carbonating? The caps are on tight, and I am sure there was still yeast in my beer... it sat in the secondary for 2 weeks after 2 weeks in the primary...

Is my beer ruined? It tastes wonderful... but it's flat!

What can I do?

 

[morrowboarder]

My wheat IPA took 3 weeks to carbonate all the way. It could be that there wasn't enough yeast in suspension when you bottled. What was the ambient temp while in the bottle?

 

[Cultkid]

Aprox 23ºC

 

[BigFloyd]

This doesn't specifically address your issue with the one problem batch, but if you have a good scale, you'll get more accurate carbonation by weighing your priming agent instead of measuring volume in a cup.

 

[ChshreCat]

Where do you have them sitting? If the one that didn't carb was sitting on a concrete floor or something like that, it could be cooler than ambient temp was. Also, if that one was higher gravity, then it can take longer to carbonate.

 

[Cyclman]

Give it time, could be the recipe, could be the yeast, lots of variables. I've had a few that took 5-6 weeks to carb fully.

 

[mavicanuck]

I've got flat beer too, they've been sitting for two weeks so maybe I could wait longer but I'm pretty sure it's from my caps leaking. When I tried to pack one upside down, over night I lost about an 8th of the contents. The pair I tried tasted fine but flat.

My kit came with metal collars that wrap under the glass lip to convert any bottle to a swing top. There's a couple holes that allow you to put the tops on tighter, but it was pretty tough to close them so I used the loosest setting.

I'd like to know if there's any way to salvage them. My plan now is to boil some water and sugar, crack em open and reclose them on a tighter setting.
Any idea if it might bottle ferment a second time?

 

[latium]

Mavicanuck, that should be fine, except I'd suggest getting the carbonation drops so you can just put a few in each bottle rather than trying to do such tiny doses by hand. The main unfortunate thing about them (IMO) is that you just drop them in, not boiling or anything first, but they're widely used (although more expensive than plain dextrose).

 

[Cultkid]

I guess I'll just wait a few more weeks and see if that does the trick.