I thought I would try to harvest yeast from a commercial beer. I made a starter with an OG of 1.040 and poured and the yeast from a 750 ml bottle. I did this last night, so it has been 24 hours. There isn't a lot of activity right now, but I didn't expect there to be. Three questions I have. Do I need to make another starter in the next few days and add it to the previous starter? Once I get the starter to produce enough yeast can I just store in my fridge until I'm ready to brew with it? Last question does anyone have a stir plate and do you recommend it? Thanks in advance.
Starting with bottle dregs (a very small cell count), you may need to step it up (crash and decant into a new, bigger starter) several times, depending on how big the beer you want to brew is. Edit: there's some good basic info on stepping up starters here... http://www.yeastcalc.com/careandfeeding.html ...along with another calculator that's more step-up friendly. Depends on how long you're talking about. A week or so is okay. Months may not be. The calculator at mrmalty.com can give you an idea about how yeast vitality drops off over time. Yes and yes. Stir plates allow you to get higher cell counts with smaller starters.
You might want to make sure that the beer you cultured from is actually bottle conditioned using the same yeast that was used for fermentation. Some are not.
I know 75 minute is bottle conditioned, but don't know if it's the same strain. I also know that if you email dogfish head, they will tell you.
You have to be careful, a lot of places filter the beer and bottle condition with champagne yeast. You would hate to go through all the effort to try and get a house strain only to end up with generic champagne yeast.
Can you give a reference to champagne yeast? I think this is suspect, as champagne yeast will go after sugars not fermented by most beer yeast, and that can result in bottle bombs. Many breweries will add a flavor neutral yeast at bottling. German wheat beer brewers often add a lager yeast at bottling.
I don't know about most breweries, but I know that all of Brooklyn Brewery's 750 mL releases are bottle conditioned with champagne yeast.
I made a mistake on that. My bad. It will go to a high ABV than the yeast used for fermentation and will overcarbonate if the primary yeast had pooped out leaving fermantable sugars behind. That is where you can get into bottle bombs.
With regard to stepping up, you might also give the yeast a better chance with a lower gravity starter wort - something like 1.020 for the first round.
That is what New Belgium uses in La Folie as stated here http://embracethefunk.com/2012/06/26/lauren-salazar-of-new-belgium-qa/ I know for a fact that two other breweries in Colorado use Champagne yeast to bottle condition and a third uses a neutral Lager yeast.
OK thanks. I am more used to reading about other breweries that will use a neutral ale or lager yeast for bottling. I can say I learned something today.
