Milk Stout - Carbonation issues

[andyn2001]

I've made three Milk Stouts is the last year, all bottled:

1. First one, priming sugar level 1.8vols - extreme fobbing through over carbonation
2. Second one, priming sugar level 1.5 vols - same result
3. Third attempt - zero priming sugar. Opened one today beer fizzed out of the bottle!!! I had noticed it getting carbed over the last 2 weeks.


Now, first two attempts I assumed I had bottled when fermentation was not complete, so for the third attempt I waited 3 weeks before bottling and had a steady gravity reading for over a week.

Today I took a gravity reading of this now fizzy stout it was 1.010, 6 weeks ago on bottling day it 1.015, so it has obviously carried on fermenting.

My question is this, is it the lactose sugar, it's meant to be something like 99% unfermentable,
but can yeast slowly break it down over time??

Or, do I need to leave the stout more than 3 weeks before bottling.....if it's still fermenting 9 weeks after brew day, how long do I wait?!!

Anyone else had similar with milk stouts? I get no issues with other beers including Porters, which I have primed.

 

[Jag75]

Never bottle one before but it went from 1.069 to 1.026. I never check my gravity until 3 weeks right before I keg . What is your OG , yeast used and FG. Gushers could be contamination .

 

[andyn2001]

I think I have elimated contanimnation as it's only happened with Milk Stouts, not my porters, or ales. To have it only happen to three beers, all Milk Stout I think makes me confiedent it's not wild yeast or similar. The lactose goes into the boil 10 mins before flame out. OG 1.053, FG at bottling 1.015, now 6 weeks later 1.010!! Beersmith est FG 1.016, so close, and it appeared to have stopped for a week. But, I'm suspected a very slow fermentation is still going on. It's much fizzier now than 2 weeks ago, 6 weeks after bottling with no priming sugar!

 

[Jag75]

That's crazy . I dont understand how it can carb up without priming sugar . Unless like you said it still fermenting . I dont know what yeast your using but if beersmith is saying its projected finish is at 16 it makes me think contamination since the yeast is done . Maybe someone here will have the answers for you. Sorry buddy , I hope you get it figured out .

 

[andyn2001]

I suspect the Lactose........can yeast slowly break it down? I used S-04. I know it's meant to be 99% unfermentable.....

 

[Dgallo]

I suspect the Lactose........can yeast slowly break it down? I used S-04. I know it's meant to be 99% unfermentable.....

Lactose is completely unfermentable to brewers yeast. 1.010 is way too low for a milkstout. If you used a 1lb of lactose that’s typically 6-10 gravity points that will not ferment. I’ve never had a milkstout finish lower that 1.018. I would suspect possible infection. 3 weeks should be completely fermented. Usually you hit fg within 5 days of your pitching the correct amount of yeast.

 

[andyn2001]

I agree with all you say.....but why has this only happened to my 3 Milk Stouts, no other beer! I don't believe only these 3 had an infection! the odds are just too big. But, if you say Lactose is 100% unfermentable then it's the only logical assumption. IT was 1.015 at bottling as I mashed at 149F.

I've bought two new ss fermenters, I'll try in them, I used to use plastic. But, all my ales and others porters no issues with carbonation.

 

[Dgallo]

I agree with all you say.....but why has this only happened to my 3 Milk Stouts, no other beer! I don't believe only these 3 had an infection! the odds are just too big. But, if you say Lactose is 100% unfermentable then it's the only logical assumption. IT was 1.015 at bottling as I mashed at 149F.

I've bought two new ss fermenters, I'll try in them, I used to use plastic. But, all my ales and others porters no issues with carbonation.

Could be the lack of Ibus, If your not hopping much in your milkstout. Hops are a natural antibacterial. are you keeping it in the primary the whole time or are you transferring it? Are you adding anything other than the yeast post boil? How are you cooling?