Sluggish Fermentation, Minimal Krausen

Hey everyone,

So, this is my third batch at this point, so I'd like to think I know a little bit more than I did two months ago...

This time I am trying to brew a licorice chocolate & raisin porter (with extract). Approximately 8 hours after I pitched the yeast, there was about one bubble every 10-15 seconds in the airlock - a much less vigorous fermentation than prior batches. Approximately 12 hours later, the bubble rate increased to about one every 2-3 seconds or so. Yet, there appears to be very little krausen. I'm worried about infection.

I also did something stupid... I set some of the beer (PRE-yeast addition) aside for the OG reading... i put it in a pint glass and covered it up with saran wrap. I then waited 2 days to take the reading... (mostly due to needing to borrow a graduated cylinder from work to do so) - but at that point, the beer that I set aside looked like it was infected. I tasted it, and sure enough it was sourish - so the numbers I read from the reading were probably not accurate.

Well, suffice it to say that I'm concerned that the weak fermentation I'm observing is a result of an infection rather than the yeast I pitched. Any thoughts?

Please let me know if there's any additional information you'd like to know in helping me address this issue. Cheers!

Here's the schedule I followed:

Steep 30 minutes:
1lb Pale Chocolate Malt
1lb German/Weyermann CaraAroma

Boil 60 minutes:
6.6 lbs Northwestern Dark malt extract
1oz Cluster hops

Last 15 minutes of boil:
1 cup of Ghiradelli unsweetened cocoa powder (~3.3 oz) (previously dissolved, boiled)
1oz licorice root
1.5 star anise seeds
~1lb (15oz) of Newman’s Own organic purple raisins (previously chopped, boiled for ~15 min)

Then 11.5 Safale s-04 Dry ale yeast added (previously rehydrated).

not all fermentations take off like a rocket, from what you described i don't see a problem, if there is an infection there is nothing you can do about it now. Not saying that there is mind you.
PS: some of the ingredients in your brew will have a slight sour/bitter taste at this stage.

I wouldn't worry.

Is this the first time you used this strain? If you used it before, was it at a similar OG and temperature?

Yeast strains are like dog breeds... they can be pretty different. Lack of krausen, different rate of bubbling... those are not necessarily problems.

Since you saw SOME sign of activity within less than a day, I would relax and test the gravity after a week or so.

Horseflesh said:

Is this the first time you used this strain? If you used it before, was it at a similar OG and temperature?

Yeast strains are like dog breeds... they can be pretty different. Lack of krausen, different rate of bubbling... those are not necessarily problems.

Since you saw SOME sign of activity within less than a day, I would relax and test the gravity after a week or so.

Click to expand...

Not only that but the same batch of beer brewed with the same kind of yeast can vary dramatically. Every one is a different animal.

Yeah, I'm definitely aware that not sanitizing the glass/saran wrap could account for the set aside beer to spoil... so I wasn't too worried about the beer in the carboy spoiling for that reason.

I've used this same strain of yeast for my last batch of beer - and the fermentation was much quicker, so I was concerned this time.

As for systematic differences, I DID shake up my carboy pretty good after pitching the rehydrated yeast this time, as opposed to last time when I basically just added the rehydrated yeast to the carboy without mixing well (perhaps this caused the yeast to mostly remain at the top of the beer and form the nice krausen that it did?)

Thanks for all your replies and votes of confidence everyone, I'm looking forward to tasting this beer because it smelled DIVINE!

Well, as an update:

I bottled my beer three days ago after three weeks in the fermenter (I didn't transfer to a secondary). There was a healthy amount of trub at the bottom of the fermenter, but the beer at this point still had a sourish bite to it (although I could definitely taste the chocolate and smell the licorice, I was assuming the sourness was the raisins that I added?).

Anyway, I bottled the beer with priming sugar and just today (after only 3 days of them being in the bottle), I noticed that all the bottles had rings on the inside of the necks. The bottles even have a solid amount of trub at the bottom, ~1/4 of an inch I'd say!

Naturally, I'm worried that this continues to be evidence of contamination, and at this point I'm further worried that I have bottle bombs. I cracked one open just now, and the beer indeed had a good amount of carbonation. It wasn't excessively carbonated to the point of fizzing out like champagne, but still more than I would expect after 3 days!

The thick trub and bottle ring is what alarms me the most... I tasted it and it's not bad... again still a slight sourish taste but it's not off putting and chocolate is definitely the dominant flavor.

Well, what should I do? Does it sound like I have an infection/bottle bombs?

My initial thought upon reading this was a cool fermentation temperature. I brewed a couple batches on Black Friday and by Sunday there wasn't any activity. I noticed that due to my 60 degree house, it prolly stalled the yeasties. I went out and bought a tote and aquarium heater and set my buckets in there. By Monday when I got home from work I had Krausen erupting out of the bottle the blow off tube was in. Altho, I can offer little info about infections, I would repeat what's been mentioned about sanitation, check you FG and when stable make sure your fermentation temps are where they should be.