Lots of messages back and forth with @S. cerevisiae to get an understanding of his process.
Here are the steps I am going by:
1. Gather the stuff needed
2.25 L water
200g DME
Glassware
Lids
Funnel
Sanitizer
Cotton
Alcohol
Yeast
2. Prepare and boil starter wort for 15 min; chill when complete
3. While chilling; sanitize glass jugs, lids, funnels, and other equipment needed
4. When chilling complete: Clean pouring lip of pan with alcohol and transfer in to 2x1g glass jug
5. Clean yeast package / vial with alcohol and add equal amounts to each starter
6. Cap jugs, and “Shake like they owe you money”
7. Rest for a few min and loosen caps
8. Pitch or crash at High Krausen
This is split to get two 1 litre starters to pitch in 10g of wort…Irish Red I am brewing on Sunday.
More to follow.
I’ve been trying the crash at high krausen method myself (although I hit my starters with O2 rather than shaking, and I put them on a stir plate at a very low RPM).
Split a vial of Irish Ale yeast from a local source that rents space at the college microbiology lab in Colorado Springs decanted until there was 30ml of yeast and medium then put half in each jug
Only have to wait a minute or so. Just to give it time for the wort to run back down so you don’t get sprayed in the face when you break the seal. After that I just leave the caps sitting on top of the jug
Most one to two liter starters that are made with a vial of White Labs yeast or an activator smack pack of Wyeast yeast should reach high krausen within 12 to 18 hours, sometimes sooner. The cells are in high gear when high krausen is reached.
As an example, my next brew day will be 5.5G of 1.05(targeted) Pilsner. Beersmith, MrMalty, and Yeastcalc all call for around 385B cells, give or take. If I buy 1 vial of WLP 833, split it as above into 2 1L starters, and shake the heck out of, what is my approximate yield cell mass? If I remember correctly Mark, maximum density in 1L is 200B cells, so I should yield roughly 400B, correct? Is this putting too much stress on half a vial, for a lager, asking it to go from about 50B to 200B in one step? Most of those calculators call for 2 vials and huge starters to get there: 6L un-stirred, for 1 vial, 4L for 2 vials, etc. I have 5L flask and 1G jug, so I can easily split into 2 vessels, just don’t want to stress my yeast. My last 2 lagers were both under-attenuated by 5 points or so. 5 points may not be much, but they both taste sweet to me, but I know they were under-attenuated. I just really don’t want a sweet pilsner. This brew day is still almost 2 weeks out, so let me know what you think
If you have a copy of Yeast, there is a table on page 140 which shows how many cells resulted from pitching 100 billion cells into various amounts of starter wort.
When 100 billion cells were pitched into 2 liters of 1.036 wort at 70 degrees, the result was 205 billion cells. When 100 billion cells were pitched into 4 liters of the same wort, the result was 276 billion cells.
However, the wort was not oxygenated nor was the starter agitated. I think that would have increased the cell counts.
I wish they had run several different iterations of the experiment to test the effects of oxygen, agitation, stir plates, etc.
Absolutely not, if you saw how little yeast I pitch into 600ml of wort, you would would never again question pitching half of a White Labs vial into 1L of wort.
Increasing the cell count from 100B to 205B cells requires the viable cells to double a little more than one time, which tells me that dissolved O2 was more than likely the limiting factor in this experiment. The requirements for this method are a starter vessel that is three, preferably four or more times the volume of the starter. Ignoring this requirement has the potential to negatively impact the results one obtains from the method. Luckily, one gallon jugs are relatively cheap.
The requirements for this method are a starter vessel that is three, preferably four or more times the volume of the starter.
Why? Is it the O2 available in the headspace, and cannot enriching the O2 percentage in the headspace allow one to “cheat” on the starter/vessel ratio to some degree? I want to do 2 starters and 8L vessels are impractical and hard-to-find! (and afford!)
