Multi-step starters

[beerking1]

I am considering using homebrew sized yeast vials to prepare a starter and grow up enough yeast for a 3 BBL batch of specialty beer in our brewpub.
Question is, how many steps would be best, and how big a starter for each step?
I have a pair of 2 L flasks, and a 5 L flask, as well as a stir plate. I am thinking of pitching 2 vials of WL Belgian yeast into 2 L of 1.040 starter, putting that on the stir plate for 2 days, and then making another step.
Should chill and decant the 2 L starter, and add another 2 L of wort, or am I better off just adding all 2 L to 3 L wort in the 5 L flask and letting that grow?
Seems to me I have read (can't remember where) that you usually get a doubling of yeast during the growth phase. I am wondering if going from 2 L right to 5 L will be enough, or if I will get more growth by doing 2 starter steps of 2 L and then the 5 L.

I also can pitch the starter into a 5 gal yeast brink, which will probably be the final step before brewing.
Thanks in advance for any advice.

[gitchegumee]

I used to do this routinely for new yeast in a 10 hl brewery. I started with oxygenated (and of course unpitched) wort from a brew in a 20 liter carboy. Fill it only half full--10 liters. Pitch the swollen yeast package and plan on another brew in two days. The 10 liters would be at high krausen two or most three days later. Now fill a sterile fermenter with 100 liters of oxygenated wort from your day's production brew and pitch the 10 liters of high krausen starter. In another two or three days, brew your batch on top of that. I've had excellent success with this method. My DME tanks had the sample valves installed on the cone right at the 100 liter mark, so I'd fill the tank until the sample valve level was reached. You may get some foam out the CIP with a fermenter at 110% capacity, but that shouldn't matter too much. The yeast obtained from this first generation would be strong and last me another 4-5 generations before I'd repitch.
So to answer your questions: Use whatever starter you have. I don't see an advantage of using two vials of yeast. I wouldn't decant the starter, but don't see much harm if it's been crashed & clarified. (BTW, I did NOT cool my yeast between steps) And I think most brewers propagate in the range of 5x to 10x volume of wort at each step. 4 gallons of high krausen wort wouldn't be quite enough for 3 bbl of fresh wort. Perhaps you could propagate in a half-barrel? Or make two starters? Good luck!

[Buckley]

I did w very similar routine as previously posted. I also kept a bag of light DME around incase I needed to make a starter and was able to pull wort from a brew. If I knew that yeast was going into a high gravity wort I would make it a 3 step process. First pitch into 2 gallons, a day or 2 later another gallon and the same once again. I was able to to an 11% tripel (8bbl)from yeast from a white labs tube.

[wiredgourmet]

Agree totally with Phillip. My method is a little different and not entirely relevant here but this business of small flasks and a stir plate is way too fussy for me.

Your brink is ideal in one sense because it allows temp control which is important with small inocula (lower temp is hostile to bacteria), but I also feel the 5 gal capacity is insufficient for propagation from such a small starting culture. If it was a bit bigger, I would say just start in the brink with 10-15L wort, then feed it wort, nutrients (sparingly) and oxygenate it periodically.

Be really, really careful; a few strangers in 5 L of slurry or barm is harmless; a few strangers in a homebrew-size inoculum is potentially devastating.

I pitch barm, not krausen wort or slurry, so I probably have little to offer by way of specific advice.

But in general, be super careful (did I mention this?); hop your medium to around 25-30 IBU (more is not protective against Gram-positive bugs and is not helpful to the yeast); 1.040 is a good density, btw; oxygenate the wort very well and if you have a sanitary means to deliver O2 periodically during propagation this is wonderful; use yeast nutrients at 2x the recommended dose for brewing; if necessary, use lactic or phosphoric to get your wort pH to 4.5 or a hair lower which many bacteria don't like; and keep the temp at or near 65F, which is somewhat hostile to many bacteria whereas yeast don't mind it at all (or the low pH either).

Good luck.

[beermkr]

When I was at Hilltop (beerking1 knows where) I used to pitch 3 gallon starters into a 8 bbl batch. Now I would never do that but I got reasonable results.

I can see making a 2L starter and then going to 3 gallons for your 3bbl batch with no problems. I would probably figure a way to continuously aerate your starter to promote massive growth.

Heck for that matter rig up a aeration stone in a carboy and make a 3-4 gallon batch from LME/DME. Pitch your two vials and put it on a stir plate.

Mike