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-   -   How to step up a yeast starter (http://www.homebrewtalk.com/f163/how-step-up-yeast-starter-283975/)

billtzk 11-29-2011 01:35 AM

How to step up a yeast starter
 
I'm targeting 1.060 OG for my next brew, which will be an American stout. I will be using Wyeast 1450 Denny's Favorite 50. I have one Activator pack manufactured Sept 6, 2011. This will be a 10 gallon brew. I don't have a stirplate yet or an O2 system (will be buying both soon, but not in time for this brew) so I'll be using my typical "intermittant shaking" method for my starter.

I always make a starter, but I usually just make a single step 1500 ml starter about a day before pitching, so I'm pretty sure I'm always underpitching my 10 gallon batches. I want to correct that this time and pitch the right amount of yeast.

Mr. Malty calculator says for my yeast date, volume, OG, yeast production date, and method, I need to start with 2 activator packs and an 8.56 liter starter. That's with the "growth factor" slider all the way to the right.

I only have 1 pack of yeast and a 2000ml Erlenmeyer flask. That size flask is only good for a 1.5 liter starter, roughly. I have a gallon jug which I think would accommodate a 2.5 liter starter, maybe a bit moer. Or a 5 gallon carboy.

I don't have a brew day picked yet, so I'm flexible on the length of time required, but I can't go pick up another pack of yeast until the weekend, and I want to get started tomorrow. How can I go about stepping up this single Activator pack to the required 417 billion cells efficiently?

michaeltrego 11-29-2011 01:47 AM

If you use your 1 gallon jug, it looks like you can get to your target pitching rate by starting with a 3L starter, and then stepping it up with another 3L starter.

brewmonk 11-29-2011 02:01 AM

step up your yeast? make beer! just make a 5 gal batch of beer, then pitch it on the 10 gal. you'll have to wait a week for the first one, but you'll be drinkin that in no time.

dezman 11-29-2011 02:12 AM

Just make your normal starter with the 2000mL then when its done decant and pour yeast into the gallon jag filled with wort for next starter (2.5L in the jug should do fine). Try to shake both starters as much as you can to help growth.

billtzk 11-29-2011 02:22 AM

Quote:

Originally Posted by michaeltrego (Post 3524959)
If you use your 1 gallon jug, it looks like you can get to your target pitching rate by starting with a 3L starter, and then stepping it up with another 3L starter.

That sounds right if I were starting with the 2 packs of yeast that Mr. Malty says I need. But I've only got one. Maybe starting with 3L and stepping up two times, 3L each, instead of once? I don't know how to calculate the yeast growth.

Quote:

Originally Posted by brewmonk (Post 3525024)
step up your yeast? make beer! just make a 5 gal batch of beer, then pitch it on the 10 gal. you'll have to wait a week for the first one, but you'll be drinkin that in no time.

Yes, I think that would do the trick too. I could easily grow a sufficient sized starter for a 5 gallon batch in a reasonable time probably without stepping it up. Something simple like a SMASH using the same hops that I plan to use for my stout would get me plenty of yeast cake to pitch for my stout.

Plus I could harvest half the yeast from my conical as soon as primary fermentation is done, and transfer the beer and the rest of the cake to a carboy to finish up. Normally I don't secondary, but in this case it would free up my conical sooner for the stout.

Thanks for that suggestion. That's definitely a workable idea. And I'd have a 5 gallon SMASH to enjoy.

billtzk 11-29-2011 02:26 AM

Quote:

Originally Posted by dezman (Post 3525059)
Just make your normal starter with the 2000mL then when its done decant and pour yeast into the gallon jag filled with wort for next starter (2.5L in the jug should do fine). Try to shake both starters as much as you can to help growth.

Yep, that was what I was figuring, but that amount of starter is predicated by Mr. Malty on starting with two packs of yeast, whereas I only have one.

michaeltrego 11-29-2011 02:33 AM

Quote:

Originally Posted by billtzk (Post 3525097)
That sounds right if I were starting with the 2 packs of yeast that Mr. Malty says I need. But I've only got one. Maybe starting with 3L and stepping up two times, 3L each, instead of once? I don't know how to calculate the yeast growth.

In Mr. Malty slide the growth factor all the way to the right. Set your OG, viability date and intermittent shaking. Then play with the volume until the number of vials is 1 and liters of starter is 2.99. This should show 4.28 gallons (which doesn't really matter at this point), and you will see that it results in 178 billion cells. This is your first step starter. Now uncheck the viability box and put 178 in the viability %. Change the volume to 10 gallons. You will see 2.8 liters are required to grow 178 billion up to to 417 billion cells. This is your second step starter. Voila.

billtzk 11-29-2011 02:59 AM

Now that is a clever way to use the calculator. But why does starting with 178 % viability equate to 178 billion cells?

Sulli 11-29-2011 03:08 AM

Or you could use this. It correlates with Mr. Malty, and is much easier to use. Enter the info for your wort. Then set the date of your smackpack, then enter 3 liters with intermittent shaking for the first step, and 3 liters with intermittent shaking for the second step, and you are there.

michaeltrego 11-29-2011 03:15 AM

Quote:

Originally Posted by billtzk (Post 3525229)
Now that is a clever way to use the calculator. But why does starting with 178 % viability equate to 178 billion cells?

I learned that trick from Thirsty Boy. Mr. Malty assumes 100 billion cells of 100% viable yeast in one vial in a perfect world. So your viability will go down if your yeast has an older production date, or it can go up if you imagine your starter is mega "vial" of really fresh yeast.


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