General Category > Yeast and Fermentation

Stepping up a Starter

(1/3) > >>

goybar:
Hi All,

I'm making a 5.5 gallon batch of Munich Helles with an OG: 1.049, FG: 1.014.

According to MrMalty's Pitch rate calculator I will need a 378 billion cells, based on my WLP830 use by date (may-30-2010) I will have 88% viability.

So I will need a 3.66 Liter starter with on vial of yeast on a stirplate.

I have a 1 Liter Erlenmeyer, hindsight a very poor purchase.

I also have a 1 gallon jug.

3.66 Liters is basically 1 gallon, too much to create the starter in.

How do I step it up?

A.  1L starter decant and add 1L starter

B.  1L starter decant and add 2L starter

C.  2L starter decant and add 1L starter

D.  2L starter decant and add 2L starter

E.  Other

Thanks

Chris

dean:
If it were me, I'd use the gallon jug and start with two and a half quarts until it finished, crash it and decant, let the yeast warm to about the temperature of your second addition of one to one and half quarts of wort and let it finish.  You should have enough yeast cells if not more than enough.  jmo... but I'm no expert at starters either.

goybar:
Yes, I will be using my 1 gallon jug, but what I'm not sure of is how to get to the correct pitching level.

I don't want to over or under pitch the yeast.

trying to figure out the step yeast amounts is fuzzy math to me...

Chris

a10t2:
I love the MrMalty calculator, but doing two-stage starters with it can be frustrating.

One simple alternative is to use the Wyeast calculator (http://www.wyeastlab.com/hb_pitchrate.cfm). It does have some limitations: works only in gallons, no adjustment for viability, and gives results as pitching rate rather than cell count, without allowing for decanting the starter.

BTW: I'm assuming you can't get a stir bar to turn in your gallon jug, so I'm using "intermittent shaking".

Anyway, here's how to spoof MrMalty:
1. Set your production date, then play with the gravity and/or volume fields to get the volume of your first stage (I'll use 1 L).
2. Note the number of cells that grows (178B).
3. Turn off the automatic viability calculation and enter that number for the viability.
4. Enter your real gravity and volume, and the calculator will tell you the volume of the second stage (2.24 L).
5. Verify that the volumes are realistic and adjust the first-stage volume if needed. Ideally, you want to at least double the volume at each step.

When making the starter(s), be sure to allow enough time to chill and decant at each stage before stepping up.

dhacker:
Why is your gallon jug too much to create a starter in?

Sounds like the perfect solution to me.

If, (as a10t2 states) it's because your stir bar won't spin, then a Dumbbell style stir bar is just the ticket.