I have 4 Wyeast 2633 Octoberfest Lager Blend smack packs and want to get enough yeast to brew a lager for my 14.5 conical. Mr. malty says I need around 900 billion cells. I have a 5 L flask and a 2 L flask with only one sitir plate. What is the best way to step up to this crazy amount of yeast cells? Mr. Malty says to just toss in all 4 in a 5 L starter. Is it that easy?

Do you have a pot or another container you could use? I normally start out with 2 packs into a 2 gal starter in a SS spaghetti pot on a stir plate.

I've also used a 1 gal glass pickle jar for ales.

What about brewing a smaller beer, like a Vienna lager, and re-pitching the appropriate amount of slurry.

You could pitch three packs in a 2L starter in your 5L flask, let it ferment out, chill, decant, and add another 4L of starter wort into the flask. That should get you close to that number.

Or you could brew a five gallon starter batch as bhass suggests.

Thanks for the replies. I usually use dry lager yeast for lagers because it is easy to get your cell count. I have to use these 4 smack packs up before they go out of date. Once I get the cell count up, the rest is a simple of matter of harvesting it and use it again. Of course I have to keep everything clean.

What about pitching 4 packs in 4 L?

I generally estimate that 1 pack into 2L will double if fermented out. I don't have Yeast in front of me to reference the table in there. There is a diminishing return in terms of growth by pitching more yeast in less wort (4packs in 4L will grow less than 1 pack in 2L, though you'll still end up with more yeast).

I think you'll need to step up a couple times, or make a starter beer as suggested earlier.

When you say that you need to use them by the expiration, how close are they? That will also affect the viability of your yeast, and if they are older, you may need to step them up even more to get the numbers you want.

A moth old now. I can't brew for at least 2 weeks, but I guess I have time to step up.