Help with yeast calculation

[crashlann]

If I am brewing a Belgian Strong Ale and my OG is going to be 1.084, when I enter the data in Mr.Malty, it tells me I need 2 vials of yeast with a starter and intermittent shaking, and 1.63 liters of starter needed. I use a 2 liter starter Erlenmeyer flask. What is the 1.063 liters of starter referring to? It states a growth rate of 3.0, what is this referring to? I think I am overpitching and getting off flavors due to understressed yeast. Can anyone help me here? I get two different results whether using the website or Android. Thanks.

[Ozwald]

If I am brewing a Belgian Strong Ale and my OG is going to be 1.084, when I enter the data in Mr.Malty, it tells me I need 2 vials of yeast with a starter and intermittent shaking, and 1.63 liters of starter needed. I use a 2 liter starter Erlenmeyer flask. What is the 1.063 liters of starter referring to? It states a growth rate of 3.0, what is this referring to? I think I am overpitching and getting off flavors due to understressed yeast. Can anyone help me here? I get two different results whether using the website or Android. Thanks.

I've checked out the calculator, but never really used it. IIRC there's a setting of how thick your slurry is, which would effect the total starter volume that you pitch. The 1.063L is estimating an appropriate cell count calculated from the thickness & total volume. Personally I would pitch 1 vial into a ~1/2 gallon of 1.040 wort, swirl it as much as possible until it finishes, decant & pitch it. If you have a 3 gallon carboy, I would consider going up to a 1.5 gallon starter wort, but .5g should be plenty sufficient.

[crashlann]

Actually I use a 6 gallon carboy for fermentation but a 2 liter Erlenmeyer flask for starters. Maybe I wasnt clear on this. Thanks for feedback!

[spiderwrangler]

and 1.63 liters of starter needed. I use a 2 liter starter Erlenmeyer flask. What is the 1.063 liters of starter referring to?

What volume are you actually looking at? I run by the general process that Ozwald stated... I do a 1040 in 2L on a stirplate with one vial and figure that generally will give me close to double. A lot of it can vary based on yeast viability, which you don't really have any true way of knowing ahead of time.

[Ozwald]

Actually I use a 6 gallon carboy for fermentation but a 2 liter Erlenmeyer flask for starters. Maybe I wasnt clear on this. Thanks for feedback!

You were clear. I was talking about a 3 gallon carboy for the starter.

[MRbrew]

Jamils calculator is based on a 1.040 starter gravity. You get this by adding DME to water at a rate of 1:10. So a 1.63L starter requires 163g of DME to make 1.040. The 3.0 growth tells you that there will be cell growth of 3 times what you put into the starter. 1 vial contains 100 billion yeast cells, you're pitching 2 with 3x growth so will end up with 600 billion cells. This is a big beer and requires a lot of yeast. Over pitching means less growth and less production of the yeast flavours, but you won't get this doing the above. The only other tip I can suggest is plenty of oxygen at the start and another burst or 2 before 12 hours is up and the yeast head into anaerobic phase. The extra O2 helps the yeast build healthy cell walls and cope with the large amount of sugar. If you're using pure O2 too much will cause a hot alcohol flavour, stick to air and you can't over do it.

[spiderwrangler]

and the yeast head into anaerobic phase.

In terms of breaking down sugars, it's pretty much all anaerobic, since the yeast aren't using the oxygen for aerobic...

[brewinhard]

If you are concerned about pitching enough yeast, and are adding some simple sugars to your beer as many belgian styles require, then you could always leave out the sugar from the kettle which would reduce your OG allowing you a smaller pitch rate which would be healthier for your yeast. Then as fermentation begins to slow (day 5 or 6) you can boil your sugar in a small amount of water (1 cup or so), cool it, and add it to your fermenter to help the yeast finish the fermentation.

Oxgyen additions are a good start too and very beneficial for yeast health and reproduction. As long as you maintain proper temp control (with a 1.084 OG) you could easily blast your chilled wort with up to 90 sec. of O2 with no ill effects. Do try to keep the pitching temp no higher than 68F and try to keep those temps for at least 36 hours before letting the temps rise for best ester and phenolic production. Different yeast strains will respond differently to pitching rates, oxygen availability, and temperature. Take good notes as always.