Which Yeast Pitching Calculator Do You Use

[brew_darrymore]

Hi all,

I have been playing around with a few online yeast pitching calculators only to discover that the results they produce differ immensely. These are the calculators I refer to:

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

http://www.brewersfriend.com/yeast-pitch-rate-and-starter-calculator/

http://www.brewunited.com/yeast_calculator.php (homebrewdad's)

http://yeastcalculator.com/

http://www.yeastcalc.co/yeast-pitch-rate-and-starter-calculator


The problem as I see it lies in the way viability is calculated by each calculator.

For example, I have a White Labs tube that has an expiry date of September 20, 2015. Once I put in the production date (4 months prior to Sep. 20, ie May 20, 2015), I get the following viability results by each calculator: (in the same order as above)

10%

7%

36% (!)

33%

4.6% (!)


Well, that's not very encouraging! So, I have somewhere between 4.6% and 36% viable yeast in the tube? That completely messes up the starter volume and final yeast count.

So, which yeast calculator do you use?

 

[SEndorf]

Your yeast is fairly old. I've played with Mr. Malty a few times which always seems to require more yeast than necessary.
I use the Beersmith yeast starter tool which has been very accurate for me. Plugging in your date, it comes to 33% viability which seems right. You will need 2 vials with a stir plate, and 3 vials without.

 

[brew_darrymore]

Your yeast is fairly old. I've played with Mr. Malty a few times which always seems to require more yeast than necessary.
I use the Beersmith yeast starter tool which has been very accurate for me. Plugging in your date, it comes to 33% viability which seems right. You will need 2 vials with a stir plate, and 3 vials without.

Thanks very much for your reply.

I know, it's an old vial of yeast, but it's salvageable. I was thinking of stepping it up, but the different calculators would suggest different starter volumes.

I should probably add Beersmith's calculator to the poll as well.

 

[Ungoliant]

I like using Brewer's Friend. It's pretty straightforward and highly modifiable for my needs. I have a 2L flask, so doing starters for big beers is difficult because they usually require bigger starters than I can make.

However, what I usually am able to do with Brewer's Friend is tweak the size of my step-ups until I get a 2-step starter that I can make with my size flask that also meets my required pitching rate. I've had good results from doing it this way, and have had nice clean fermentations that hit FG with no issues.

Honestly, I would recommend starting with a small starter (Maybe 400-800 mL)and maybe doing a 3-step starter, depending on your limitations.

 

[brew_darrymore]

I like using Brewer's Friend. It's pretty straightforward and highly modifiable for my needs. I have a 2L flask, so doing starters for big beers is difficult because they usually require bigger starters than I can make.

However, what I usually am able to do with Brewer's Friend is tweak the size of my step-ups until I get a 2-step starter that I can make with my size flask that also meets my required pitching rate. I've had good results from doing it this way, and have had nice clean fermentations that hit FG with no issues.

Honestly, I would recommend starting with a small starter (Maybe 400-800 mL)and maybe doing a 3-step starter, depending on your limitations.

Thanks!

Stepping it up is the way to go.

What puzzled me and triggered this post is how different the viabiliy of the yeast is according to the various calculators. A range between 4% and 36% viability could be the difference between a normal fermentation and a heavily underpitched one.

 

[max384]

I also prefer Brewer's Friend. I also use their hydrometer temperature calculator and brewhouse efficiency calculator.

 

[JONNYROTTEN]

For what is worth if you swirl trub after racking and pour in a mason jar you can dump it in the next batch without worrying much about having a yeast issue...and save money.Ive yet to use a calculator and have yet to have a problem fermenting...just sayin

 

[brew_darrymore]

For what is worth if you swirl trub after racking and pour in a mason jar you can dump it in the next batch without worrying much about having a yeast issue...and save money.Ive yet to use a calculator and have yet to have a problem fermenting...just sayin

Been there, done that

It's a new strain of yeast though, that I purchased some time ago but didn't have time to brew. I want to use the expired vial.

 

[stpug]

For example, I have a White Labs tube that has an expiry date of September 20, 2015.

A WL vial starts life with no less than 100 billion cells - likely more.
Today is September 30, 2015 - 10 days past best used by
If the vial was purchased from a reputable source and stored refrigerated since then, then I assume minimal loss.
I would probably assume minimal loss and estimate 80 billion cells are still viable with low vitality. Making a starter takes care of their vitality, and use 80 billion as your inoculation rate.

We're playing with grenades here - not darts

 

[brew_darrymore]

A WL vial starts life with no less than 100 billion cells - likely more.
Today is September 30, 2015 - 10 days past best used by
If the vial was purchased from a reputable source and stored refrigerated since then, then I assume minimal loss.
I would probably assume minimal loss and estimate 80 billion cells are still viable with low vitality. Making a starter takes care of their vitality, and use 80 billion as your inoculation rate.

We're playing with grenades here - not darts

80 billion cells sounds quite optimistic! I hope you're right. The vial was stored in my fridge the entire time.

Bringing back the calculators, none of them suggested a number this high. Moreover, yeastcalc.co predicted only 4.6 billion viable cells.

 

[pricelessbrewing]

I use homebrewdads, which is based entirely on Kai Troesters data and assumes a 20% loss per month. Note that this is not saying 100-20-20-20-20-20=0% at 5 months but rather that each month 20% of the beginning viability for that month is lost. This is saying that 100*.8*.8*.8*.8*.8=33~%

You should note however that the initial cell count has little impact on the ending cell count, within reason. The INNOCULATION rate is what matters, and is why stepping up your starter with low cell counts is important. Brewunited shows you this piece of information, and gives you rough ideas on where you want to be.

Do a simulation starting at 5B, 10B, 25B, 30B, 50B, and 100B. You get pretty much the same total cell count until your inoculation rate is near one of the gray areas.

Moreover, I love the overbuild feature for two reasons. One is that it informs new brewers about the concept (as many brewers are still not aware of harvesting from starters and I think it should become common practice as it's easy to do, and lowers costs considerably) and two is that I just find it super useful for doing a single starter for 2+ brews and a harvest. Find out what each beer needs, set your beer OG to 1.0000 then overbuild is the total amount of yeast wanted. Done. Probably not an "intended" method, but it works out for me.

Many people have done cell counts and have found kai troeser formulas to be more accurate than mr malty was. Not sure what the situation was, but it's been shown.


In my opinion, the only thing that could be improved upon would be if a yeast company made a stir plate model and released it for free and tailored it to be specific for each individual yeast characteristics. Each yeast has a different cell count density, so different total cell counts, and each one has it's own properties on growth based on innoculation rate. As far as I know, this hasn't been explored fully but it is true for various yeasts. I vaguely recall a user posting on here that he worked for a yeast company working on one like this, which would be awesome, and while it was fairly recent I can't remember who or where they said it.

 

[stpug]

80 billion cells sounds quite optimistic! I hope you're right. The vial was stored in my fridge the entire time.

Bringing back the calculators, none of them suggested a number this high. Moreover, yeastcalc.co predicted only 4.6 billion viable cells.

It is (optimistic), but that's how I would approach it. I've also seen variance on viability between yeast strains, but would probably stick with the 80billion estimate. Perhaps it's worth an email to White Labs posing this question just to see if you get a response and what the response is. They are pretty good about responding, but it sometimes takes a couple days. Tell them the strain, the best used by date, how it's been stored, and ask if there's an estimated value (range) of viable cells that you should work from when building a starter - vitality should be low whatever the range. See what they say.

 

[brew_darrymore]

It is (optimistic), but that's how I would approach it. I've also seen variance on viability between yeast strains, but would probably stick with the 80billion estimate. Perhaps it's worth an email to White Labs posing this question just to see if you get a response and what the response is. They are pretty good about responding, but it sometimes takes a couple days. Tell them the strain, the best used by date, how it's been stored, and ask if there's an estimated value (range) of viable cells that you should work from when building a starter - vitality should be low whatever the range. See what they say.

I might as well send White Labs an email. Thanks for the suggestion.

The strain I'm dealing with is WLP530. I am planning a Belgian pale ale.

 

[stpug]

I've found Belgian strains to be some of the most resilient strains in my collection (antwerp, farmhouse ale, trappist, pranqster) based on performance and end product characteristics.

 

[frankktankk]

I use brewers friend and "Braukaiser - Stirplate" and always assume that I have 1B cells (1%), then it should never be an underpitch.
If an "exact" pitchrate is requested, a cell count is needed (microscope, colour and hemocytometer).

 

[brew_darrymore]

I use brewers friend and "Braukaiser - Stirplate" and always assume that I have 1B cells (1%), then it should never be an underpitch.
If an "exact" pitchrate is requested, a cell count is needed (microscope, colour and hemocytometer).

That's a very conservative approach, assuming 1B cells. I'll play with it though. Thanks!

 

[brew_darrymore]

I'm just giving an update on my starter.

I made a 1.6L starter yesterday morning. 36 hours later I have a beautiful blowoff!

The 14-day expired WLP530 vial seemed to be perfectly fine, perhaps, among other things, due to the fact it was shipped with an ice pack from a reputable online store and it was stored in my fridge the entire time.


Thank you all for your responses! It was interesting to learn your individual approach to yeast pitching calculations.

 

[gb81]

I have recently developed www.yeaststartercalculator.com. Feel free to try it and let me know your thoughts/comments. Lets you calculate the amount of DME, pitching rate based on the style your are brewing, the viability of your yeast, and allows up to 3 step ups using various formulas, including Chris White's and Kaiser's. Also added an FAQs section which will be updated with more FAQs and links to articles regarding making a yeast starter.

 

[ChuckS1]

No way to calculate overbuilding the starter? Seem you’ve just reinvented the wheel. What sets it apart from all the other calculators.

 

[yowzers]

I use dry and throw in one pack. Harvest a pint mason jar for three more uses and then use another pack. Making great beer that way.