50mL of viable yeast - how big of yeast

[rwing7486]

Hey everyone, I have in my fridge 50mL of viable Danstar Bry97 West Coast ale yeast that I harvested using the top crop method (99% yeast). This yeast I have already used in 3 consecutive beers and am looking to pitch into my Black IPA this weekend. My SG will be 1.067. So my question is how big of a yeast starter should i make given the 50mL concentration? is 1 liter a big enough of a starter?

According to Mr. Malty I will need 243b yeast cells to pitch into this beer.
If i reverse engineer from the "re pitch from slurry" tab from Mr. Malty I roughly have 120b viable yeast cells in the 50mL of slurry. So I am trying to determine how big of a starter I will need to grow from 120b to 243b.


Thanks

 

[eddiewould]

When I'm making a yeast starter, I ignore the initial cell count and consider only the cells I'd expect as growth based on the amount of fermentables (e.g. 1L of 1.040 wort) I provide.

So from my perspective the final cell count of 20 billion cells into 2L of 1.040 wort is - for all intents and purposes - the same as 1 billion cells into 2L of 1.040 wort.

 

[Big Monk]

Hey everyone, I have in my fridge 50mL of viable Danstar Bry97 West Coast ale yeast that I harvested using the top crop method (99% yeast). This yeast I have already used in 3 consecutive beers and am looking to pitch into my Black IPA this weekend. My SG will be 1.067. So my question is how big of a yeast starter should i make given the 50mL concentration? is 1 liter a big enough of a starter?



According to Mr. Malty I will need 243b yeast cells to pitch into this beer.

If i reverse engineer from the "re pitch from slurry" tab from Mr. Malty I roughly have 120b viable yeast cells in the 50mL of slurry. So I am trying to determine how big of a starter I will need to grow from 120b to 243b.





Thanks

This is probably a high estimate. I believe 1.2x10^9 p/mL is more accurate depending on viability.

 

[Big Monk]

^
This.

Where slurry is concerned I believe you'll find that 1.2x10^9 cells p/mL is a more accurate number for slurry.

Your 50 mL of slurry would therefore have ~(50x1.2)=~60x10^9 cells.

Now say you use the "Shaken, not Stirred" starter method using a 1 gallon jug and 1250 mL of starter wort. The maximum cell density for 1250 mL is ~250x10^9 cells.

This is of course an estimate. Home brewers are only dealing in estimated cells numbers.

I definitely agree that one should gauge their starters by the maximum cell density that the starter volume can provide as opposed to any of the values in the calculators.

 

[rwing7486]

^
This.

Where slurry is concerned I believe you'll find that 1.2x10^9 cells p/mL is a more accurate number for slurry.

Your 50 mL of slurry would therefore have ~(50x1.2)=~60x10^9 cells.

Now say you use the "Shaken, not Stirred" starter method using a 1 gallon jug and 1250 mL of starter wort. The maximum cell density for 1250 mL is ~250x10^9 cells.

This is of course an estimate. Home brewers are only dealing in estimated cells numbers.

I definitely agree that one should gauge their starters by the maximum cell density that the starter volume can provide as opposed to any of the values in the calculators.

I ended up creating a 1.8L starter with a gravity of 1.040. Added the 50mL of yeast at 3pm on 12/24 to my starter on a stir plate. I woke up on 12/26 at 8am and turned off the stir plate and began my brew day . It's now 1:45am on 12/27 and only half of the starter has fallen off/cleared up. I still see the yeast earing sugar (still half the flask filled with yeast in suspension ). I currently have my award winning black IPA recipe in the basement at 68 degrees F @ 1.066. I'm going to wait until the starter is finished before I aerate with pure O2. I plan to decant starter and then pitch into the 1.066 wort. Also I have tin foil over the flask, should I worry about infection? By infection I mean wild bacteria in the air after 3 days? When I won with this this recipe back in 2014 I pitched rehydrated bry97 yeast from its original package.

 

[Big Monk]

By the time I started doing yeast starters, I had heard about the "Shaken, Not Stirred" starter method so I can't speak to stir plate starters.

I'm not sure what your concern is. In that long a period of time, unless bacteria "owned" your starter in some way, shape or form, you should be good.