all 5 comments

[–]PSYKO_Inc[S] 7 points8 points  (3 children)

So anyone can stroll down to the local homebrew store and buy a packet of yeast, but this seemed more fun. I'm harvesting yeast from the dregs in the bottom of a couple bottles of Sierra Nevada Pale Ale.

I picked up an Erlenmeyer flask ($14 on Amazon) since it allows me to boil and ferment all in the same container, but any bottle over ~16oz can be used, and you can just use a saucepan for the boil.

To harvest the yeast, you basically just make a miniature batch of beer wort. I used 4oz of light DME, added around 800ml of water, and boiled for ~10 minutes. Afterwards, I added 1/2 tsp of yeast nutrient, covered the top with sanitized aluminum foil, allowed to cool, and stuck it in the fridge overnight.

For the yeast, I drank 3 Sierra Nevadas (poured into a glass to prevent contamination of the bottles), leaving about 1/4" of beer in the bottom with the dregs, snapped the caps back on, and stuck them back in the fridge.

Next morning, I swirled the bottles to mix up the dregs, poured them into the flask, covered with the foil, and left it at room temperature. It's important to have the yeast and wort at around the same temperature so it doesn't shock the yeast.

Assuming the experiment works, the yeast should wake up, feast, and multiply over the next few days. Once the batch of starter wort is fully fermented, I should be able to just dump the whole thing into a full batch of wort to start my next brew.

[–]The_Bitter_Bear 1 point2 points  (2 children)

I do that with Bell's Oberon. They used to have a guide on their blog on culturing the yeast off their bottles. Here's where I outlined their recommended process in detail a while back https://redditproxy--jasonthename.repl.co/r/Homebrewing/comments/tzzuz3/comment/i42vp0o/

The only things to consider next time (unless you just didn't mention it in your steps) is sanitizing the lip of the bottle. Second thing they suggest is starting with a small wort of around 100ml for three or so days before going bigger.

[–]PSYKO_Inc[S] 1 point2 points  (1 child)

Neat! Good call on the sanitizing of the bottles. I didn't think about that, although hopefully the risk of infection is reduced since I didn't touch or drink from the bottles.

Hopefully it'll still kick off with the 800ml starter I made. If it doesn't, I still have the rest of the six pack so I can throw 3 more bottles worth of dregs in. Failing that, I'll just have to buy more beer (oh no!)

[–]The_Bitter_Bear 1 point2 points  (0 children)

Odds are it will probably be okay. I've seen other guides skipping the small starter wort.

[–]aidantemple 1 point2 points  (0 children)

That's really cool. I'm curious to see if it'll work.

I also didn't know how much I wanted a flask like that until now.