EDIT: Please be sure you read through all of the posts in this thread before coming to any conclusions. This first post asks as many questions as it answers, so be sure to read through the excellent posts that follow for a more complete picture. And please continue to post on the subject if you can bring even the smallest bit of information to the table.
A quick search found one post on the subject, which I've included as a good jumping-off point. Here is the following from Frank Dillon:
As I'm new to all of this yeast propagation business, I don't yet have a bunch of canned starter wort. I know that's a common practice among brewers who step up yeast for larger batches, so I would love to get some advice on starter wort recipes, canning, etc. Looks like I'll soon be adding mason jars to my collection of brewing equipment.Starter OG of 1.040 is what I have read (Palmer book) but it doesn't go into detail as to why to stick around that gravity. http://www.howtobrew.com/section1/chapter6-5.html
The only reason I can think of is at the time of the writing autolysis was a pretty scary situation. However he has come to state more recently that autolysis is very unlikely in normal more up to date brewing practice (including not racking to secondary) because we are getting much better/younger/healthier yeast from labs that specialize in brewing yeasts.
That being said I routinely make higher gravity starters based on the desired ABV of my final beer. I calculate the OG by using the ABV and assuming a FG of 1.000 (just to not over do it, I know it will not get that low). So for a beer that will be 7% ABV I aim for a starter of 1.053. Since the yeast can tolerate higher ABVs and I always use the starter yeast within 7 days I have never had a problem. Also "over pitching" might be brought up but I only use a 2L flask and I do this to maximize the yeast. I have talked to a couple LBG members that have said over pitching is like having too much money, is it really a problem?
In the meantime, I will have to make do with a DME solution to step up my yeast. As Frank (and conversations I've had with Andy) suggest, the common suggestion is a SG of 1.040 for your wort used to step up the yeast. But Frank's suggestion about higher alcohol beers "sounds right" to me, and since the one I'm brewing this week will be a 7% beer, I'll aim for 1.053. (I'm assuming that you used BeerSmith to calculate that desired gravity, and could do the same for whatever ABV your final beer will be.)
Fermcap (foam control drops) is also highly recommended in your starter, so you don't make a big mess. This should keep your yeast from foaming over the rim of your flask and making a mess all over your new stir plate and anything else you might have on that table.
For those of us who don't have starter wort canned, or don't brew often enough to warrant making a big batch of starter wort, is there a suggestion on what kind of DME is best for starters? I'm assuming Light DME, which is usually Carapils-based, I believe. But perhaps it depends on the final beer you're making, and for some instances, Dark or Amber DME might be a better choice? In the end, the spent wort is getting decanted off and only a very small amount is going into the beer, so maybe it doesn't matter one bit. Thoughts on this are welcome.
Palmer offers the following on preparing your starter wort using DME:
Now, I'm planning two steps of around 1500ml each (for my 2L flask to allow a little headspace). Since one pint is roughly 473 milliliters, I'm thinking I'll need about 3.3 times the 1:1 mixture Palmer describes above for each step. That's 3.3 pints of water to 1.65 cups of DME for an SG of 1.040. Please correct me if I'm overthinking this...Boil a pint (1/2 quart) of water and stir in 1/2 cup of DME. This will produce a starter of about 1.040 OG. Boil this for 10 minutes, adding a little bit of hops if you want to. Put the lid on the pan for the last couple minutes, turn off the stove and let it sit while you prepare for the next step. Adding a quarter teaspoon of yeast nutrient (vitamins, biotin, and dead yeast cells) to the starter wort is always advisable to ensure good growth. It is available from your brewshop.
Obviously, you want to chill your wort after boiling and keep it sanitary before pitching your yeast. I'm using a 2L Erlenmeyer flask on my stir plate, so I'll sanitize that, add the cooled wort to it and then pitch the yeast. Cover with a sanitized piece of aluminum foil (or airlock if you prefer), and put it on the stir plate. In about 36 hours, the yeast will have blown through the wort, and it will be time to cold-crash the yeast. In about 24 hours, the yeast will have settled out, and you can decant (pour off the spent wort, leaving the yeast cake in the bottom), and then add more room temp starter wort for the second step.
I've been told you can figure one step per five gallons of final beer. Is there a diminishing return on this? What's the largest pitch you've ever used, and for how large of a batch? I'm a big fan of pitching big. Some discussion on the pros (and any cons?) of pitching big would be good to include. The first things that come to mind include: your initial fermentation will start significantly faster and take much less time, which means less time for a potential infection, a greater ability for the yeast to clean up after itself resulting in fewer off-flavors, fewer stressed-out yeast as they can focus on consuming sugars rather than multiplying (resulting in fewer off flavors in the first place), and shorter time from fermenter to bottle/keg. If you can speak authoritatively on yeast and the off-flavors they can be responsible for, etc, that would be a nice addition to this reference, but I'll skip it, as I'm mostly concerned with process right now.
Cold crashing between steps will get the yeast to floc out fully, so you don't decant off too many yeast cells between steps. On average, how long does cold crashing a 2000ml volume take? I've heard roughly 24 hours. Is there an ideal temp? Can you get too cold and harm the yeast?
While we're on the subject of yeast storage and such, anyone who wants to add something on freezing or making slants, it would make a good reference for later when I get to that point. Right now I don't have a lot of cold storage space, and what I do have is filled with hops. But someday it would be cool to have a nice collection of yeast strains, so I don't have to purchase as much. Of course I say that now, but buying a $7 vial or smack pack is probably a thousand times easier, more efficient, cheaper, and more likely to produce great beer than farming my own. Still, it would be cool to know how. (You know, for when the zombie apocalypse comes and we're forced to make beer without the benefit of awesome yeast labs.)
If you're brewing a 10 gallon batch, two 2000ml (2L) steps are recommended. Cold crash and store cold until you're ready to pitch (ideally as soon as it's floc'd out). Decant until you have just a small amount of liquid above your yeast cake, swirl it up real good to get the yeast in suspension and not sticking to the bottom of your flask, and then pitch onto the 70-80 degree wort of your brewed beer in your fermenter. Apparently, you don't have to worry about temperature shock going from cold yeast to warm wort. Only when going from warm to cold. I'm told the yeast actually love jumping from a cool fridge into your room temp fermenter. (Kind of like jumping from a snow bank into a hot tub. Exhilarating!)
I'm sure I'll have more as I go through my first starter. The process is easy enough, but I'm writing this with the mind-set of a beginner, so that it will be a good reference for brewers of all experience levels.
Proper yeast handling and pitching rates are some of the best and easiest things you can do to improve the quality of your fermentation and the resulting beer. Plus, when you pitch big, your initial fermentation is significantly faster, which means less time for a potential infection, a greater ability to clean up after itself resulting in fewer off-flavors, and shorter time from fermenter to bottle/keg.
This thread is open to anyone with expert advice or questions of their own. Please add to it so it can become a good community resource on the subject.
And again, my thanks to everyone who's helped make this next adventure in brewing a fun and easy one for me.
Matt
