Yeast starter calculators- OG not an issue?

[thadius856]

Yeah. unless I was out of it yesterday. I started my boil with 1.6L and ended up with 1.25 after 15 min boil. Thats what I meant. I never tossed any out.

You have a 1.4 gal/hr boiloff rate on your stove? That's pretty darn high.

You just need to maintain the boil, not be roiling like crazy. We're not trying to caramelize the sugars or increase the gravity, just sanitize the water and DME by denaturing bacterium.

Feel free to boil starter wort with the lid on. We usually leave the lid off of AG wort we plan to drink because we're trying to boil off DMS which leads to a corn taste. But since we don't care about the taste of the starter wort, just its fermentability, feel free to lid it up. Just be aware that it's easier to boil over that way, so a few drops of FermCap-S goes a long way.

So the northern brewer website has a yeast calc PDF and the 2nd step up is way smaller than the first, I just don't get the logic. 1 L starter, decant and pitch into .5 L starter? I thought you ere supposed to increase the volume at least 4x..

2nd step doesn't have to be larger than the first. You'll just get diminishing returns each additional step assuming the same amount of wort each time.

The idea being that as the cell count continues to grow, more and more of the sugars are used to sustain the existing cells and less to split off new cells.

1L into 0.5 L sounds a bit too small for this application.

 

[sethlovex]

Thanks Thaius

This all makes sense

 

[sethlovex]

1L into 0.5 L sounds a bit too small for this application.

Check this link:

http://www.northernbrewer.com/documentation/YeastPitchingRates.pdf

They say 338 billion cells...am I missing something?

 

[thadius856]

No, you read that right.

YeastCalc puts it at 128b new cells for the 1st step, 34b new cells for the second step. That seems about right to me. And that's with a stir plate. MrMalty is usually with a few % of YeastCalc.

At a generous 1.5 b/g DME, that stepping should give 225b new cells.

As I said before, because of the exponential growth pattern of yeast, getting within a factor of 2 is good enough to make great beer.