Yeast Units

[cmfso]

Hello anda thank you in advanced.
Is there any way/chance to have yeast units in gr/Kg instead of pkg?

 

[Oginme]

And you can define a pkg as a gram or kilogram.

I do this when I repitch yeast or build a culture up from a plate.  I do my cell counts as a dilution of 1 gram of slurry in 100 grams total fluid and therefore my counts are in millions of cells per gram of slurry.  At this point, I don't care what the software label is, I have my needs expressed in x million cells per gram and the pkg then equals grams.

 

[brewfun]

And you can define a pkg as a gram or kilogram.

Once the package unit is defined, the starter tab will calculate your slurry repitch in the "yeast packs to use if no starter" field.

 

[dtapke]

Oginme, can you elaborate a bit on that?

I've just started banking and counting my yeast cells, and while I'm pretty comfortable with my pitching rates, i'm not using a package unit in beersmith as you are and it sounds like it could be helpful.

at this point all i do is select the yeast pack i want, check the starter calculator to see how many cells i need, and then calculate my starters manually. If i could select it as it sounds you are it would perhaps take away a step?

I still am unsure if i could really get it down as beersmith only supports two step starters. so i would have to start with an first step that would actually be my third most likely. But i think I've got my process down enough to consistently hit about the same numbers on step three.

 

[Oginme]

dtapke,

Glad to!

I don't worry about the size of my yeast starters so much as just make sure they are of sufficient size to give me enough viable cells to draw from.  The day that I brew, I pull the flask or jar with the yeast from the refrigerator, pour off excess wort from the top and make sure the remaining slurry is fluid enough to pour.  I then sample and do a count of the total cells and viable cells in the slurry.  This gives me usually a number between 1 and 2 billion cells per gram of slurry.

I go into BeerSmith and edit the yeast so that the 'package' size represents the number of cells per gram of slurry.  From this, the program will project on the yeast starter page how many grams of slurry that I need for that recipe.  I can then update the recipe with that number of grams to weigh out and then record my actual weight measured and pitched once finished.  Pretty easy as Brewfun indicated.

 

[dtapke]

Ok, so say i've got 1.4b/ml, using a ml=g you're putting a "package" as 1.4B cells, and then it tells you how many ml or g you need.

well that makes too much damn sense. why didn't i figure that out...

I still really wish there were far more options for building multi step starters, and starting from cultures in beersmith. i find myself using my own table for yeast starters, as i'm often pitching 2-3 trillion yeast cells from a single colony. takes more than two steps to do that

 

[Oginme]

When stepping up from a plate, I usually pull off about 5 to 10 colonies (depending upon health and size) and rinse my loop into a 25 ml flask with about 10 ml of a 1.020 - 1.024 gravity wort.  Once this starts growing, I add another 10 ml of wort to keep the cells happily multiplying.  My next step is into a 200 ml flask with another 100 to 120 ml of 1.040 wort and from there to a 2 L flask with around 1500 ml.  This has reliably given me around 150B to 200B cells which I can chill, decant the spent wort and then split into 2 2L flasks for enough cells to make a couple of my batches (if lagers) and 4 to 5 batches for ales.

Again, exact amounts don't really worry me for the starters as I will draw from that to provide enough viable cells for each batch.

 

[dtapke]

half barrel to 1 barrel batches here, so my process is a bit different but similar, a little bigger step up on the last step there.

I go off the chart Jamil & Chris made for the "Yeast" book, which i've expanded into my own set of multiple charts for ease of use.