Check if fermentation has occurred.

Question

I brewed an ESB from extract just before the weekend and then got called away this weekend and wasn't able to make any observations for the next 3 days. I checked after 12 hours and didn't see any bubbling but after coming back home 3 days later there still wasn't any bubbling happening. I did take a reading with the hydrometer that came out around 130 (~100 F). What sort of hydrometer reading would assure me that the primary fermentation occurred while I was absent?

I also ended up pitching my yeast (liquid, and I think London style/type) at probably too high of a temperature because of a crappy digital thermometer that was malfunctioning so this is why I'm concerned that fermentation may or may not have kicked in.

edit: This is just my second batch and the first one was a while ago. Also there does appear to be a ring of crud just above water level and it appears that some sediment is forming on the bottom of the container (around a centimeter). Also my hydrometer reading is 1.020 (1.035 OG roughly adjusted for temp).

Link to pictures to show crud ring and sediment:

Answer 1

Well that pic with the "crud" looks like whats left after a perfectly normal fermentation to me. You'll see that ring of brown scum (we call it "krausen"), along with floating dots of the same brown stuff on the surface of the liquid. Just leave the beer alone for another 3 weeks (if your recipe calls for racking to secondary, just ignore it), then bottle it up and enjoy!

Several of the British strains of yeast are known for their very fast fermentation. I use Fermentis S-04 Dry yeast all the time and it's a workhorse. A little lag (6-12 hours) then heavy fermentation for 2-3 days, then it starts dropping. Great stuff.

Also, if you are using liquid yeast, its best to make a yeast starter before you brew to wake the yeast up and check their viability. I'd recommend you get that technique down before using liquid yeast again.

Answer 2

A reading of around 1.007 - 1.010 would probably be around what you're looking for.

EDIT: At 1.020 you are nicely on-track to getting where you want to be.

Have you brewed before this batch? I think I would know if fermentation by the state of the fermenter. Is there a ring of crud above the fluid level, or does it look pretty much the same as it did before you left it for 3 days?

EDIT: Your pictures show the tell-tell signs that fermentation is well underway.