How do you culture a yeast strain?

I was curious if there were any videos or past threads, or if anyone wanted to give their insight on how you culture a yeast strain from a beer. Im asking because Ive read some recipes for Bell's Two hearted ale and they say to specifically clone the recipe you need that particular yeast strain. How do you get the yeast from a bottle of bells two hearted ale?

Make a yeast starter from the yeast slurry from the bottom of the bottle. There's plenty of info out there on making yeast starters in general. You will likely want to do multiple starters, stepping up the size each time, to keep the yeast happy. Just remember the rule of thumb that you should not exceed a 10:1 step up ratio - ie - each starter should be no more than 10 times larger than the previous one. I would think a 100ml starter for the yeast from the bottle, stepped into a 1L starter once the first ferments out, would be sufficient, though you could add another step in between if you wanted.

It also helps if you have a couple of the same beers. When I was culturing up Pacman, I used the slurrys from 3 bottles of Dead Guy Ale. I was getting kind of slurry by the end of it...

I have experimented a bit with culturing yeast from bottles. Note that only some bottle conditioned beers actually use the same yeast that was used for fermenting the beer -- so it pays to do your research on a new beer you are unfamiliar with (this is a good, but outdated site: http://www.nada.kth.se/~alun/Beer/Bottle-Yeasts/ ).

Here is my procedure:
1. Spray cap and neck of bottle with Star San (or alcohol) before opening, uncap, then wipe the lip with alcohol and/or flame with torch/burner.

2. Add a small amount (~100 mL) of sterile wort directly into the bottle. Also add a pinch of yeast nutrient. Cover with sanitized foil and put in a warm place for 12 hours.

3. Prepare 400 mL of sterile wort in a sanitized 2L flask. Add a pinch of yeast nutrient. Aerate/oxygenate well and/or put on a stir plate. Sanitize the neck and mouth of your bottle again, and dump the bottle contents into the flask, then cover with foil. Culture for 12 more hours.

4. Step-up the starter again using an addition of about 1 L of sterile wort and another pinch of yeast nutrient. This will bring up the starter volume to about 1.5L (you can do more or less depending on the brew you are using. Make sure to aerate/oxygenate REALLY well and/or use a stir plate. After 24 hours, it is ready to pitch directly, or you can crash chill it to separate the yeast from the beer and just pitch the slurry.

Hope that helps!

FWIW, this is a fairly good write up with pictures: http://www.haveahomebrew.net/PGYSFH.doc

I also have the First Steps in Yeast Culture book (based on reviews on this site). If you are interested in yeast culturing, it is a must have.

also research the beer you're taking yeast from.

if the beer was filtered, there wont' be yeast in it to harvest.

if there is yeast sediment in the bottle, it might be the strain they use for carbonating, not what they used for primary.

its not uncommon for them to filter after primary and then use a different strain to carb it. harvesting that strain isn't gonna give you the right yeast profile.

other than that, seems like most people try to harvest a few bottles worth just to have a bigger starting culture, fewer 'step ups' to get a pitchable quantity.

Ryan_PA said:

FWIW, this is a fairly good write up with pictures: http://www.haveahomebrew.net/PGYSFH.doc

I also have the First Steps in Yeast Culture book (based on reviews on this site). If you are interested in yeast culturing, it is a must have.

Click to expand...

Ryan - Thanks for the useful info.