Which yeast pitching calculator do you use? Prefer one over the other?

[jturkish]

Mr. Malty looks to be a popular choice but I'm told it's factoring 20 billion yeast cells per gram for dry yeast

Mft of most dry yeasts say they have 6-7 billion per gram

then there's brewer's friend which looks to factors in 10 billion cells per gram

Any preferences? Be somewhat conservation and go with brewers friend, super conservation and go with mft numbers, or go balls out with mr malty?

 

[BobBailey]

After looking at Mr. Malty and Brewers Friend I have a problem with their viability estimates. White Labs tells us that the production date is 4 months prior to the Best by date. When I enter the production date in either of the calculators they come up with viability in the mid 30% range. I doubt that White labs would tell you to pitch 34 to 36 billion cells to a 5 gallon batch of even a small beer. They do want you to like the beer you make with their yeast. I would guess if the vial had been stored under reasonable conditions the viability would be much higher.

I Use Beersmith and think their viability numbers are a lot more realistic in the mid 40% range. After seeing the results of tests conducted by woodlandbrewing I believe that even Beersmith may be a bit conservative.

I do believe they would all rather err on the safe side and agree with them. Since I'm just beginning to make starters I think I'll go with Beersmith and see how that works out. I have used Brad's products for a long time and trust him.

 

[jturkish]

Wyeast and white Labs claim 100 billion cells per pack/vial. Do we know how much there actually is in a pack given 100% viability

For the most part i stick with dry yeast. Brewers friend doesn't show viability for dry yeast. Do we know the actual number of yeast cells per gram of dry yeast? Mft only claims 6 bill, one study showed 20 bill under a microscope but was told to not be accurate by one of the mft

If i assume there's 10 bill per gram and the viability is 76% does that mean actual cell count is 7.6 billion per gram?

 

[BlueHouseBrewhaus]

I've been using YeastCalc just because I initially had some issues getting Mr. Malty to work on my Kindle. I suspect YeastCalc uses the same algorithms as Mr. Malty and other sites. It also seems to be pretty conservative on age/viability percentages but I'd rather over estimate than under. So far, no issues with YeastCalc. I haven't detected any signs of under (or over) pitching even on big beers of 1080+.

 

[user 141939]

I like yeast calc. I thinks it easier to use. Mr malty, idk that sliding thing at the bottom makes me angry. I'm not gonna use more than one vial...

 

[TheZymurgist]

HomeBrewDad just put one up on his blog, and it's the best I've seen. Definitely the best functionality, and seems pretty accurate. There have been a number of articles that I've read recently on viability, so do some research on that. I think you'll find that most calculators err on the conservative side.

http://www.homebrewdad.com/yeast_calculator.php

 

[masonsjax]

I'm not condoning my behavior, but I have pitched onto yeast that was dried to the bottom of a carboy and sitting for at least 4 months unrefrigerated. It took off like I pitched a large starter and the beer was great! Again, I'm not recommending anyone mistreat their yeast like this, but I am convinced that all the calculators are extremely conservative.

 

[BrotherBock]

I like brewersfriend. It seems easier to interface with. I get to select yeast density, with what feels like more ease. The % of yeast solids on Mr.Malty seems not very exact. I never know where to place it and it seems to assume I'm harvesting yeast to get my yeast slurry. Brewersfriend does not. I can just look at my slurry and calculate density based of of the assumption that 40%-50% yeast solids= 1.2 billion cells/ml

 

[Talgrath]

Mr. Malty looks to be a popular choice but I'm told it's factoring 20 billion yeast cells per gram for dry yeast

Mft of most dry yeasts say they have 6-7 billion per gram

then there's brewer's friend which looks to factors in 10 billion cells per gram

Any preferences? Be somewhat conservation and go with brewers friend, super conservation and go with mft numbers, or go balls out with mr malty?

As far as dry yeast manufacturers, they conservatively list their dry yeast as having a certain amount per gram because that is the guaranteed amount for its lifespan (usually 4 years). Generally speaking, dry yeast has a viability of 20 billion cells per gram, or about 220 billion cells total. If dry yeast didn't have that viability, you couldn't inoculate a 5 gallon batch of 1.060 OG beer as their instructions say you can (note that smack packs are plagued by the same inaccuracies). Fortunately, for brewer's friend you can plug in your own numbers on dry yeast, which is nice.

Generally, I go with Brewer's friend, it has a bit of a friendlier interface and I can plug in my own numbers on dry yeast or a slurry and I can also select what sort of pitching rate I'm aiming for. Brewer's Friend also tells me approximately how far above or below I am on cell count; for some beers I like to slightly underpitch for additional ester flavor and on some beers I slightly overpitch for a cleaner finish.

 

[Talgrath]

HomeBrewDad just put one up on his blog, and it's the best I've seen. Definitely the best functionality, and seems pretty accurate. There have been a number of articles that I've read recently on viability, so do some research on that. I think you'll find that most calculators err on the conservative side.

http://www.homebrewdad.com/yeast_calculator.php

It's a little rough on the eyes, but that does seem to be pretty handy. I'll have to play around with that one a bit.

 

[WoodlandBrew]

Yes, 20 billion cells per gram is value that is commonly used to convert CDW to number of cells. Brewers friend may be assuming 50% viability which is pretty much what you would get if you just dumped the yeast into water and shook it up.

Personally I just use 1g of extract of every billion cells I need to grow and when I do count them it's been pretty close.
Details here:
http://www.woodlandbrew.com/2013/03/side-by-side-starters-4-of-4.html

If I had to choose an online calculator I would choose Kia's equation on brewers friend. It's the only one I know of that uses data from yeast actually grown on stir plates. (Chris White's experiments were done without any agitation. You can read about it in Yeast.)

 

[jturkish]

As far as dry yeast manufacturers, they conservatively list their dry yeast as having a certain amount per gram because that is the guaranteed amount for its lifespan (usually 4 years). Generally speaking, dry yeast has a viability of 20 billion cells per gram, or about 220 billion cells total. If dry yeast didn't have that viability, you couldn't inoculate a 5 gallon batch of 1.060 OG beer as their instructions say you can (note that smack packs are plagued by the same inaccuracies). Fortunately, for brewer's friend you can plug in your own numbers on dry yeast, which is nice.

Generally, I go with Brewer's friend, it has a bit of a friendlier interface and I can plug in my own numbers on dry yeast or a slurry and I can also select what sort of pitching rate I'm aiming for. Brewer's Friend also tells me approximately how far above or below I am on cell count; for some beers I like to slightly underpitch for additional ester flavor and on some beers I slightly overpitch for a cleaner finish.

On the brewers friend site there is a link toa page quoting the 20 billion cells pre gram. It then goes on with saying the 20 billion count isn't accurate

I wish i knew an actual number

 

[Talgrath]

On the brewers friend site there is a link toa page quoting the 20 billion cells pre gram. It then goes on with saying the 20 billion count isn't accurate

I wish i knew an actual number

Unfortunately, you can't get an exact answer unless you are a microbiologist with the proper microscope, education and lab setup. Large pro craft brewers usually have a yeast specialist or a yeast biologist to maintain their yeast lines or they farm it out to a place like White Labs for exact results. The yeast a home brewer uses, by contrast, has possibly been stored at an improper temperature at some point and/or has had some other issues in transportation that has caused issues. That said, usually the following numbers work: for a dry yeast 20 billion cells per gram (somewhere around 220-230 billion) unless they are older than six months. For smack packs, once the pack has sat three hours as per instructions, you usually have approximately 200-220 billion cells unless older than two months. For liquid vials, I usually follow the labels and I do the math if it's older than 1 month. That said, keep in mind that the very worst thing that can happen is a vast underpitch, your beer will be a little too estery and you might need to repitch, but it will still be beer. Ale yeast, at least, is usually pretty tolerant, if you're a couple dozen billion cells or less off, you'll still get a tasty beer.

 

[WoodlandBrew]

You can infer the numbers that I got in this experiment:
http://www.woodlandbrew.com/2013/01/how-many-cells-are-in-package.html

I agree that although 20 billion per gram is the standard number used for conversion, the actual number will vary.

 

[jturkish]

Here is the article i was mentioning

http://www.danstaryeast.com/articles/cell-count-and-glycogen

It says. ...

"You might also consider that you will find much higher cell numbers under the microscope than by plate count, even if you have 100 % viability because you do not always have a single cell forming a colony but rather two or more cells"

 

[user 141939]

We used these at my old lab. They have to incubate for 5 days at a certain temp.

http://www.flinnsci.com/store/Scripts/prodView.asp?idproduct=18779

 

[lolblackmamba]

Does anyone have any knowledge about the different growth rate models used by brewersfriend? I get significantly different results if I use Braukaiser stir plate or Chris White's stir plate model.

Example:

Take a starting yeast count of 3 billion cells.
Starter gravity: 1.040

Scenario A:
Starter size: 0.5L
Ending cell counts:
Braukaiser: 83 billion cells
C. White: 20 billion cells

Scenario B:
Starter size: 1L
Ending cell counts:
Braukaiser: 163 billion cells
C. White: 21 billion cells

The C. White model says the growth rate is maxed out at 6.0, explaining the different results.

Last week I made a starter from a Wyeast 1968 smack pack. Pitched some and aliquoted the rest into 50ml conicals. I counted one of the aliquots and got 3 billions cells and now I am not sure if this will be enough to make a one-step starter based on what brewersfriend is saying. 163 billions cells would be enough for what I am planning so I may just have to test it myself.

Before I do, does anyone else have any empirical evidence for which model should be used?

 

[WoodlandBrew]

C.White's Model comes from non-aerated, non- agitated cultures. These are then scaled by some magic number. Kia's comes from data taken actually using a stir plate. His experiments were then duplicated by others.

If you are using a stir plate then I would recommend using Kia's model.