Author Topic: Mr Malty Pitching Rate Calculator for Washed Yeast  (Read 6600 times)

Offline SpanishCastleAle

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Re: Mr Malty Pitching Rate Calculator for Washed Yeast
« Reply #15 on: May 05, 2011, 04:52:40 AM »
Good info Sean.

That pic just looks like vials of different amounts of settled yeast to me.  The 25% one has ~2.5x the settled yeast as the 10% one and so on.  It doesn't look like it's really telling you anything except how to eyeball 10% of a vial (or whatever).  Am I missing something?

Offline BrewQwest

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Re: Mr Malty Pitching Rate Calculator for Washed Yeast
« Reply #16 on: May 05, 2011, 06:11:01 AM »
I agree with the above post...  However, I did find the web page on Wyeast's site. The photo of the vials is at the bottom of that page:  http://www.wyeastlab.com/hb_pitchrates.cfm  
I think what the image may be trying to portray is the amount of pure yeast in those vials as compared to a mixture of yeast/trub which people may have in their containers.  Wyeast says you need 1.5 to 2 times the amount of yeast pitch from a slurry as compared to their normal pitch rate. I may be wrong about the photograph though...
« Last Edit: May 05, 2011, 06:15:51 AM by BrewQwest »
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Offline anthony

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Re: Mr Malty Pitching Rate Calculator for Washed Yeast
« Reply #17 on: May 05, 2011, 03:33:42 PM »
Good info Sean.

That pic just looks like vials of different amounts of settled yeast to me.  The 25% one has ~2.5x the settled yeast as the 10% one and so on.  It doesn't look like it's really telling you anything except how to eyeball 10% of a vial (or whatever).  Am I missing something?

Well, if I remember right, those are 25mL vials, so with the numbers (like 1.4e9) they're also showing you what different pitching rates look like after they flocculate.

Offline SpanishCastleAle

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Re: Mr Malty Pitching Rate Calculator for Washed Yeast
« Reply #18 on: May 06, 2011, 05:36:50 AM »
Good info Sean.

That pic just looks like vials of different amounts of settled yeast to me.  The 25% one has ~2.5x the settled yeast as the 10% one and so on.  It doesn't look like it's really telling you anything except how to eyeball 10% of a vial (or whatever).  Am I missing something?
Well, if I remember right, those are 25mL vials, so with the numbers (like 1.4e9) they're also showing you what different pitching rates look like after they flocculate.
Thanks Anthony.  I just went to that Wyeast page and it doesn't say how big the vials are.  Unless I'm doing my cipherin' wrong (or the answer is over an order of magnitude different than the 4.5 billion/mL), they must be larger than 25mL.  Using the 10% example: 10% of 25mL is 2.5mL which corresponds to 2.5E8 cells (i.e. 250 million).  That's only 100 million per mL.

Offline anthony

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Re: Mr Malty Pitching Rate Calculator for Washed Yeast
« Reply #19 on: May 06, 2011, 07:42:12 AM »
Good point.. I can't find the original reference for that page either, but I'm sure it was somewhere on the NorthernBrewer forum.

Online tschmidlin

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Re: Mr Malty Pitching Rate Calculator for Washed Yeast
« Reply #20 on: May 06, 2011, 11:10:30 AM »
Those look like the 50 ml falcon tubes my lab uses.

Left to right, 15 ml, 50 ml, 50 ml flat bottom (free standing).

Tom Schmidlin

Offline SpanishCastleAle

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Re: Mr Malty Pitching Rate Calculator for Washed Yeast
« Reply #21 on: May 06, 2011, 11:32:56 AM »
Those look like the 50 ml falcon tubes my lab uses.

Left to right, 15 ml, 50 ml, 50 ml flat bottom (free standing).


That was also the size one of the guys in that NB thread used for an experiment.

I think I was wrong in an earlier post when I said the vial should be bigger than 25mL in order to get closer to the 4.5B/mL number.  They tell you the cell count and a bigger vial would just mean the same cell count in even more volume (5mL vs 2.5mL in my example above).

Online tschmidlin

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Re: Mr Malty Pitching Rate Calculator for Washed Yeast
« Reply #22 on: May 06, 2011, 12:00:33 PM »
I think I was wrong in an earlier post when I said the vial should be bigger than 25mL in order to get closer to the 4.5B/mL number.  They tell you the cell count and a bigger vial would just mean the same cell count in even more volume (5mL vs 2.5mL in my example above).
Well, those really look like 50 ml tubes to me.  By your method, that would give slurry concentrations of:
50.0 M/ml, 50.4 M/ml, 49.7 M/ml, 50.0 M/ml, 50.9 M/ml

But maybe that is not what the picture is actually showing.  Is it possible that each tube was filled with 50 mls of slurry at the concetrations listed, and then allowed to settle?  And the amount of settled yeast is then listed as a % of the volume?

If you put 50 mls of 2.5E8 cells/ml in a tube and let it settle, you've got 12.5 B cells in the tube taking up 10% of the space, and the settled yeast is at 2.5 B cells/ml. .

50 mls of 6.3E8 cells/ml settles out to 25% of the space and holds 31.5 B cells in 12.5 mls for 2.52 B cells/ml.

Running the rest of the numbers the same way gives you ~2.5 B cells/ml for all of those slurries.  This seems more likely to me.
Tom Schmidlin

Offline SpanishCastleAle

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Re: Mr Malty Pitching Rate Calculator for Washed Yeast
« Reply #23 on: May 06, 2011, 12:43:44 PM »
I think I was wrong in an earlier post when I said the vial should be bigger than 25mL in order to get closer to the 4.5B/mL number.  They tell you the cell count and a bigger vial would just mean the same cell count in even more volume (5mL vs 2.5mL in my example above).
Well, those really look like 50 ml tubes to me.  By your method, that would give slurry concentrations of:
50.0 M/ml, 50.4 M/ml, 49.7 M/ml, 50.0 M/ml, 50.9 M/ml

But maybe that is not what the picture is actually showing.  Is it possible that each tube was filled with 50 mls of slurry at the concetrations listed, and then allowed to settle?  And the amount of settled yeast is then listed as a % of the volume?

If you put 50 mls of 2.5E8 cells/ml in a tube and let it settle, you've got 12.5 B cells in the tube taking up 10% of the space, and the settled yeast is at 2.5 B cells/ml. .

50 mls of 6.3E8 cells/ml settles out to 25% of the space and holds 31.5 B cells in 12.5 mls for 2.52 B cells/ml.

Running the rest of the numbers the same way gives you ~2.5 B cells/ml for all of those slurries.  This seems more likely to me.
That sounds reasonable, thanks for that.  I tried to backtrack that guy's experiment in the NB thread but didn't know the viability of his original pitch into the starters.  If I chose a reasonable viability of 75% and then tweeked the Mr Malty calculator such that I was using 1 vial and exactly a 1L starter and then used the total cell count of that starter...then divided that by the 70mL settled slurry the starter produced...the numbers were in the 2.5B/mL ballpark.