29 replies to this topic

[Poptop]

[font="calibri;"]Hi All,[/font]

 

[font="calibri;"]If you were going to use slurry from a mid range gravity (1.052) beer to make a second mid range gravity beer, and you have approximately 24 ounces of said slurry, approximately how much (in ounces) would you pitch?  I’ve done this in the past guesstimating 10 ounces and did quite well.  I was just wondering if anyone had more of a science to their slurry pitch rate.[/font]

 

[font="calibri;"]Thanks, Mike[/font]

[positiveContact]

maybe you could use yeastcalc to estimate how much yeast you grew.  you could also let it settle out in a jar in a fridge for a few days and get a pretty good indicator of how much yeast you've got.

[Poptop]

I wish I could find the article that suggested there is no more or less viability in the whole slurry than there would be in any one layer in the mason jar.  That's why I shake up and pitch (some).

[positiveContact]

I wish I could find the article that suggested there is no more or less viability in the whole slurry than there would be in any one layer in the mason jar.  That's why I shake up and pitch (some).

 

i was only suggesting to let it settle so you could estimate how much yeast you had.  when it's all mixed up i'm not sure how you could really estimate the yeast density short of figuring how much yeast you had in total.  this is only one path though.  you could possibly estimate how much yeast you created in total (using yeast calc) and pitch the appropriate percentage of your total slurry.

Edited by TheGuv, 08 July 2013 - 07:47 AM.

[HVB]

Maybe weigh it?

 

https://braukaiser.c...hing-by-weight/

[SchwanzBrewer]

Know anyone with a microscope and some plates?

[positiveContact]

Maybe weigh it?

 

https://braukaiser.c...hing-by-weight/

 

it seems like he'd need to know the cell density though.  maybe I'm missing something - I only skimmed.

[Poptop]

With all respect due to you's guys, I'm sorta lurking for a dumb'd down approach more than what I'm currently bringing or not bringing when pitching.  Things like; how long the slurry's been sittin in the fridge and/or "I typically use the whole cake for XX gravity etc.

[SchwanzBrewer]

Maybe weigh it?

 

https://braukaiser.c...hing-by-weight/

 

The only problem with doing that is that decanting the spent wort off leaves some beer weight in there. There probably aren't any numbers, but one way I thought about doing it was to take a 1000 mL graduated cylinder letting the yeast chill in it. Then when the cake is compacted measure how much you have. After that you need some way to correlate it. One way to do that is to make a 1L starter where you know pretty much how much yeast you are making and compare in another cylinder.

Edited by SchwanzBrewer, 08 July 2013 - 07:58 AM.

[MyaCullen]

With all respect due to you's guys, I'm sorta lurking for a dumb'd down approach more than what I'm currently bringing or not bringing when pitching.  Things like; how long the slurry's been sittin in the fridge and/or "I typically use the whole cake for XX gravity etc.

Mr. Malty has a calculator for how much slurry to pitch

 

https://www.mrmalty.com/calc/calc.html

[JMcG]

Less than 3 days old, pitch half.  More than three days add fresh wort to slurry for one day and pitch half.  More than a week old, make a starter.

[positiveContact]

With all respect due to you's guys, I'm sorta lurking for a dumb'd down approach more than what I'm currently bringing or not bringing when pitching.  Things like; how long the slurry's been sittin in the fridge and/or "I typically use the whole cake for XX gravity etc.

 

I think the most dumbed down approach I would go for is to use yeastcalc.  it should literally take you minutes to figure out.  if you want, give me all of the information about your brew and I'll do it for you.

 

I need to know how much yeast you pitched in, the OG, and how many gallons of beer.  from here I could estimate how many cells you got out of the beer.  from there I could say something like, use half of the total slurry or use a third or whatever.

[positiveContact]

Mr. Malty has a calculator for how much slurry to pitch

 

https://www.mrmalty.com/calc/calc.html

 

I've found yeastcalc is much better.  Just my opinion though.  I used to use mrmalty.

 

Less than 3 days old, pitch half.  More than three days add fresh wort to slurry for one day and pitch half.  More than a week old, make a starter.

 

I'm not sure he'd need to make a starter after a week.  storage is an issue as well.  how do you start the counting anyway?  since active fermentation stopped?  since he racked?  since he put it in the fridge?

[JMcG]

 

I've found yeastcalc is much better.  Just my opinion though.  I used to use mrmalty.

 

 

I'm not sure he'd need to make a starter after a week.  storage is an issue as well.  how do you start the counting anyway?  since active fermentation stopped?  since he racked?  since he put it in the fridge?

Just a ballpark, works OK here.

Hopefully cake would go in the fridge same day it was racked and assumed racking after primary done and D-rest 1 day.

[positiveContact]

Just a ballpark, works OK here.

Hopefully cake would go in the fridge same day it was racked and assumed racking after primary done and D-rest 1 day.

 

a lot of homebrewers leave a beer in primary for 2-3 weeks before racking.  this is one of the reasons I don't generally use the slurry for subsequent batches.

[JMcG]

 

a lot of homebrewers leave a beer in primary for 2-3 weeks before racking.  this is one of the reasons I don't generally use the slurry for subsequent batches.

So, you never re-pitch?

I usually re-use 2-3 times, but try to do it quickly to keep the yeast fresh.

After 2-3 brews (a month to 6 wks) I'll usually start a fresh tube from slant and build a starter, but that takes a week or so.

[ChefLamont]

Less than 3 days old, pitch half.  More than three days add fresh wort to slurry for one day and pitch half.  More than a week old, make a starter.

 

 

For the OP i would think this is a good quick rule of thumb.

 

Really, if you have had good experience with your 10oz, then I would go with that.  The reality is that there are a LOT of factors that go into the yeast health and viability that it really is a crap shoot and any rule of thumb here or anywhere makes many assumptions on those factors.

 

If you really want the way to figure out the right pitch, you need to get a microscope, a hemacytometer, and some methylene blue stain.  With them, you can count and calculate the viable cells in the slurry and then calculate the proper pitch rate from there.

 

Beyond doing that, it is all just hand-waving estimations and approximations.  Like I said, I would just stick with your 10 oz if it consistently gives good results and no fermentation related (especially yeast stress) off flavors.

[MyaCullen]

 

I've found yeastcalc is much better.  Just my opinion though.  I used to use mrmalty.

 

 

I'm not sure he'd need to make a starter after a week.  storage is an issue as well.  how do you start the counting anyway?  since active fermentation stopped?  since he racked?  since he put it in the fridge?

I hadn't noticed Yeastcalc having a slurry tool 

 

I used Yeastcalc two batches ago for my Helles last week, reached terminal gravity at 48F Ambient in 6 days, I am more than happy with that.

[positiveContact]

I hadn't noticed Yeastcalc having a slurry tool 

 

I used Yeastcalc two batches ago for my Helles last week, reached terminal gravity at 48F Ambient in 6 days, I am more than happy with that.

 

I like the options that yeastcalc has overall.  i also like that it uses kai growth estimate which I think might be more in line with reality.

[MyaCullen]

 

I like the options that yeastcalc has overall.  i also like that it uses kai growth estimate which I think might be more in line with reality.

I liked his growth estimate much better, and his explanations of why

 

I will be using it in the future to get my 1450 going that's a bit on the elderly side