Did it ferment or not?

I brewed and pitched the yeast on Sunday but ended up having to go out of town. I asked my wife if the airlock on the brew bucket was active. She said she had no idea. I have been watching the airlock for the last 12 hours and it looks dormant. How can I tell if the yeast I used was good or if I need to repitch? If I need to repitch, any tips? I have never had this happen before.

 

Take a hydrometer reading. If it's lower than it was on brew day, your yeast worked.

 

I failed to take a hydrometer reading before I left.

 

If it was a kit it probably listed what the OG and FG should be.

If it wasn't a kit, post your ingredients and yeast used (or plug into a homebrew calculator) and you can probably calculate your OG.

Assume you hit the listed kit OG or the calculated OG. Take a hydrometer reading and compare the two. Goodluck, hope the yeast did their thing.

 

If specific gravity is like 1.040 or higher, then fermentation is not going on fast enough and you should add more yeast. If SG is about 1.022 or less, then it might be done fermenting already but just wait a few more days just to be sure.

 

The presence of a kraeusen ring will tell you if it's been fermenting. If it's in a bucket, you can darken the room and put a flashlight on top shining down - you can see kraeusen or the ring through the side if it's been fermenting. Of course it won't tell you the SG.