Starter size question using slurry

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BurlingBrew

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I apologize in advance as it seems this topic has been covered several times but still very much confuses a beginner like myself.

I am brewing a porter this weekend with an est. OG of 1.045. Beersmith tells me I need 175.3 billion cells. The attached picture is yeast I harvested from a starter on 06/19/15. What is the best way to calculate starter size? I've attempted to use several online calculators and I've come to the conclusion I do not have enough slurry. Seems to me I should be able to grow what i have into what i need? Help! :confused:

20150707_100531.jpg
 
Found this after a quick reddit search. You'll have to figure out how many cells/mL you currently have, then use a calculator to grow it to the proper amount.

Here is a counting procedure I use after rinsing to find the concentration of my slurry. Hope it helps:
YEAST COUNTING BY DILUTION
BACKGROUND
Visual estimation of cell density is based on the eye's fairly sharp threshold for observing turbidity. When viewed in a standard 13 x 100 mm tube, yeast suspensions of less than about 1,000,000 cells per ml are not visibly turbid. Above this threshold density they are visibly cloudy. By adjusting the number of cells in a suspension until just barely visible, you can obtain a suspension of known density (approximately 1,000,000 cells/ml) and then use the dilution factor to obtain the slurry concentration.
METHOD - BALLPARK CONCENTRATION
1) Take 1 mL of well-resuspended slurry, and add it to 9 mL water, mixing well. This is your 1:10 dilution.
2) Take 1 mL of 1:10 dilution, and add it to 9 mL water, mixing well. This is your 1:100 dilution.
3) You see where I am going with this... Just keep making dilutions until the suspension is not turbid. THIS is the dilution where you have ~1,000,000 cells/mL.
4) Calculate the cell density in slurry.
This step is easy.
cell density in slurry = (1,000,000 cells/mL) * (dilution factor)
Lets say the dilution you hit where the suspension is no longer cloudy is 1:100. That means:
cell density in slurry = (1,000,000 cells/mL) * (100) = 100,000,000 cells/mL
METHOD - ACCURATE CONCENTRATION
***** NOTE: If you have a turbid 1:10 dilution, and your 1:100 is not turbid, your ACTUAL point of no turbidity may be somewhere in between the two dilutions. To be most accurate, once the dilution is no longer visible (ex. 1:100), take the last turbid dilution (ex. 1:10) and do a 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8 and 1:9 dilution of that, in this case giving a total dilution of 1:20, 1:30 ,1:40, 1:50, 1:60, 1:70, 1:80 and 1:90, respectively. Let's say the dilution where there is no longer turbidity is the 1:4 dilution (1:40 total dilution).
Then:
cell density in slurry = (1,000,000 cells/mL) * (40) = 40,000,000 cells/mL
BIG DIFFERENCE!
Hope this helps you. It works great for me. I am pretty close every time. I work in a lab and I have checked my dilutions using a hemocytometer and a microscope. I am usually within ~10% of 1,000,000 cells/mL on my non-turbid dilution, but I have accurate graduated cylinders from work. I actually now use 10 mL volumetric flask and a 1 mL volumetric pipette. Haven't measured my accuracy and precision since the upgrade, but I can only assume it's gotten better. If you do this technique, invest a small amount of money (like $20) on a nice 10 mL graduated cylinder and ~20-30 13x100 mm test tubes (or some even more accurate volumetric flasks/pipettes, though those will be a little more expensive). The tubes and the graduated cylinder can both be washed and reused. ALSO, get a nice 100 mL graduated cylinder for measuring out the volume of slurry that you calculate you need for a given batch. Knowing the cell concentration within ~10% doesn't accomplish anything if, in the end, you don't have an accurate measurement of the volume of slurry you are adding.

If that doesn't work, or seems like too much work, just pitch what you've got into a 3L starter of 1.040, let it sit on a stir plate for ~36 hours, put it in the fridge 24 hours before brewing to cold crash, then pull it out to warm to room temp ~6 hours before pitching. Once it's room temp, put in about 500mL of fresh wort and put it back on the stir plate to revitalize and wake up your yeast, then pitch the whole shebang.

You won't know the cell count, but that should hopefully overshoot, which is better by far than undershooting.

It's a bit of a pitch and pray doing it this way though, and it's far better to know what you're dealing with!
 
I realize now that there is not necessarily a simply answer to my question. Pitch and Pray it is! Thank you for taking time in gathering this info. :mug:

Does anyone else have any best practices for making starters from slurry? Ideally i would like like continue harvesting my yeast starters but am now worried about under pitching.
 
I realize now that there is not necessarily a simply answer to my question. Pitch and Pray it is! Thank you for taking time in gathering this info. :mug:

Does anyone else have any best practices for making starters from slurry? Ideally i would like like continue harvesting my yeast starters but am now worried about under pitching.

I just had a duh moment, sorry!

Just make a starter with slurry as if you are using a wyeast packet. The starting cell count of a starter doesn't matter too much, because the goal of a starter is to grow the cells to saturation in your starter wort. So really the volume of your starter will determine your cell count more than anything else!

So you can ignore all that stuff I just posted about determining your current cell count :ban: and just make a starter like normal. Pitch rate should be 6-10 million cells/mL, so if you want 200 billion cells you just need to make a 3L starter, and shake or stir plate, and follow the procedure above.

You might also find this helpful, many thanks to Gavin C for all his hard work and patience

https://www.homebrewtalk.com/showthread.php?t=532452
 
I think I'm finally getting somewhere with the yeast calculator suggested in the thread you forwarded. The initial cell count on this calculator defaults to 100 billion which is typical for a white labs vial. How do I calculate my cell count on my harvested yeast (pic attached on first post). Its quite possible I'm getting all my terminology mixed up.

Just for fun I used the default cell count of 100 billion and in addition overbuilt my cell count by 100 billion (harvesting purposes). It suggested my starter volume should be 1.5 liters (pitch 1L and harvest another 500ml) I only have a 2L flask FYI hope any of that made sense.

Does this sound right?
 
Your yeast looks very clean, no hop debris. When my harvested slurry is clean, I estimate 2 billion cells per milliliter, and use Homebrew Dad's calculator to estimate viability and starter size. I'm pretty sure I'm still over pitching, but it is much better than under pitching.
 
Your yeast looks very clean, no hop debris. When my harvested slurry is clean, I estimate 2 billion cells per milliliter, and use Homebrew Dad's calculator to estimate viability and starter size. I'm pretty sure I'm still over pitching, but it is much better than under pitching.

Yes very clean, it was harvested from my last starter. The best way to determine how many ml would be to pour and measure an equal amount of water in another jar?
 
Your yeast looks very clean, no hop debris. When my harvested slurry is clean, I estimate 2 billion cells per milliliter, and use Homebrew Dad's calculator to estimate viability and starter size. I'm pretty sure I'm still over pitching, but it is much better than under pitching.

2 billion/mL seems very high to me. Is that pure slurry or is that shaken and resuspended?
 
I'd make a 1L starter with that jar's contents and call it good. You're making a 1.045 beer - it's not like your yeast are going to war with a crazy Belgian or Russian Imperial Stout. Doing the 1L + that volume of slurry has worked for all my beers to get 'em down to 1.012 or less.
 
I'd make a 1L starter with that jar's contents and call it good. You're making a 1.045 beer - it's not like your yeast are going to war with a crazy Belgian or Russian Imperial Stout. Doing the 1L + that volume of slurry has worked for all my beers to get 'em down to 1.012 or less.

That's pretty much what Beersmith suggested. I think I'll end up doing a 1.5L and harvest of 500ML and pitch the rest.

I'll let you all know how it turns out. Thank you so much for your feedback! :mug:
 
I think I'm finally getting somewhere with the yeast calculator suggested in the thread you forwarded. The initial cell count on this calculator defaults to 100 billion which is typical for a white labs vial. How do I calculate my cell count on my harvested yeast (pic attached on first post). Its quite possible I'm getting all my terminology mixed up.

Just for fun I used the default cell count of 100 billion and in addition overbuilt my cell count by 100 billion (harvesting purposes). It suggested my starter volume should be 1.5 liters (pitch 1L and harvest another 500ml) I only have a 2L flask FYI hope any of that made sense.

Does this sound right?


Essentially yeast will multiply until the oxygen and sugar in their environment are all used up, which should result in a consistent population for a given volume and specific gravity.

My understanding of yeast, which is limited and based purely on basic internet research and a microbiologist girlfriend, tell me that the initial cell count doesn't really matter a whole lot (I'll explain the exception to this).

The only thing the initial cell count tells you is how much the yeast will need to multiply to reach saturation, more yeast need to multiply less and will get there faster, whereas fewer yeast need to multiply more and will take longer. The volume of the starter is really the main factor in how many total cells there will be. The way the calculators work makes this appear not to be the case because of which variables they manipulate, but their success speaks for themselves. So they are a valuable tool for putting you in the ballpark.

The exception that I mentioned above is if you are starting with very few cells or a small volume of starter (10mL or so). You don't want the yeast to have to work that hard to multiply and go through that many generations to consume the sugars. This can result in stressed yeast which will produce off flavors. In your case, since you are starting with a slurry that's obviously more yeast than in a white labs/wyeast pack, you don't have to worry about that.

I basically just make a 2-3L starter for everything unless the gravity is higher than 1.075 because that gets me close enough. Anything higher than that and I'll just do a step starter.

Bulosopher has lately been conducting experiments with yeast vitality being more important than cell count. (He's basically getting a smaller number of yeast cells all excited and pumped up :rockin: and pitching them side by side with conventional starters)

His initial findings seem to indicate that vitality plays a significant role in the health of your fermentation. My personal inclination (which is not backed up by any data other than how I do my starters) is that cell count DOES matter to an extent, but vitality also plays an important role.

I tend to make smaller starters than most people, but I also add that 500mL of fresh wort on brew day and stir for a few hours. I usually end up with healthy fermentation within 8 hours.

Soooo... final answer, there's a lot of right ways to make starters. About the only wrong things you can do are gravely underpitch, or dump a massive 6 liter starter into a 5 gallon batch :D Just shoot for that sweet spot of 2-3L, make sure your yeast are excited to be alive, and relax :tank:
 
As stated, you want to determine how many mL of slurry you have. You can then research and determine your cell density. Its reported anywhere from 1-5billion cells/mL. There is even a thread on HBT as how to guestimate what your density is. I cannot find it currently.

Myself, I like to assume 1.2 billion cells/mL, per Wyeast's recommendation. Do I believe this is my actual cell count? No. I believe it to be a bit higher, as I whirlpool and use a SS spider, so only wort makes it into my fermenters. I just like to be conservative, so I use that value. I'd rather overpitch than underpitch.

I use pint sized mason jars to store my yeast in, and they have convenient markings on the side telling you how many ounces or mL you have.
 

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