Weird ferment

[Russ]

Made Dave lines ESB as Daab's recent instructions using 1.6 kg of John Bull Maris Otter on Sunday, my first extract to break in my boiler

All went very smoothly and hit the suggested OG of 1047

I cooled the wort in a the sink, aerated with a paint mixer on the drill and pitched the rehydrated yeast at around 9 pm Sunday (Safale SO4)

Next morning (6am) no bubbles in airlock but a 1/4 inch thick dense dark brown foam on top, bit weird but I thaught all was well.

Returned from work (4.30 pm), still no air bubbles, in airlock, the yeast just looked like it was sat on top, not able to get to the wort below....... Still just a thick 1/4 inch dense dark foam on top.....

.....So I stirred it in

......within a hour or so airlock was going crazy and a normal white foamy
head 2'' thick appeared, still going strong.

What happened?, Never had one of these before....

[bitter_dave]

My guess is that the lid wasn't properly sealed before, so the c02 was not going through the airlock because there was no pressure. The fact that there was a yeast head indicates that it was fermenting anyway

[Russ]

Yeah thanks, thats what I thought initially, but it was sealed, if I squashed the fermentor I got bubbles through the air lock.

It wasn't what I'd call a yeast head, just a thick crust . It's got a propper head and ferrmenting like the clappers now so no worries, just weird.

Cheers

Russ

[mooj]

The brown crust is likely to be trub, you will get varying amounts depending on the kit used, it's fairly harmless. It's highly likely that this will float as soon as the fermentation starts. When I used to fit an airlock I found it would only bubble when the fermentation was going strong. It is likely that the initial gas produced will escape through minute gaps in the seal as it offers the least resistance. When it's really going it will still leak through the seal, although it's producing so much it will puff the lid up and force itself through the airlock as well. I could be wrong but I doubt any fermentation bin seal is airtight.