At what cell counts is starter most necessary?

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mcberry

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Apologies if this has been answered - I couldn't find the answer via search.

I am making a Trippel on Saturday - should be around 5 gallons at 1.095 and will use WLP500. I had originally planned on making a 3L starter. Due to time and other constraints I won't be able to get to the homebrew ship in time to make the starter, crash cool it, and decant.

I plan on just using 2 vials in lieu of a starter. This would give me between 140B and 280B cells according to White Labs. According to Mr. Malty I need 321B cells, so I will underpitch.

My question is at what range is a starter most important. I am guessing 200B and needing 300B will be less of an impact that having 50B and needing 150B and so on... That is, is the need for a starter linear, or does the need diminish as the actual cell count increases?

The FAQ at White Labs seems to imply this fact, but doesn't really give a solid answer:

If less yeast is pitched into beer, more yeast growth takes place, so more flavor compounds such as esters are produced. Depending on the amount produced, this is how pitching rates can have a direct effect on flavor profile. If 5 to 10 billion cells are pitched into wort, this definitely has a negative flavor impact in terms of higher ester levels and potential for bacterial contamination. But does a pint starter worth of yeast (30-50 billion cells) pitched into beer tasted different then 2 liters worth of yeast (250 billion cells)? Sounds like more homebrew has to be made to get to the bottom of this!

Any thoughts are appreciated.
 
As the white labs FAQ stated, this really hasn't been looked at. Regardless, the goal is to maximize yeast growth to have proper fermentation of your wort, by whatever means at your disposal.

Possible options:
Make a starter, but pitch without decanting.
or
Pull 3L of your Wort, pitch into that. Let it go overnight, pitch into your fermenter. Yes, you are risking contamination by leaving your wort overnight, but I would think it should be fine if your sanitation is good.
or
Pitch 4 vials (or whatever) of yeast to get the required cell count (expensive option)
or
pitch what you have and call it good.
 
The idea is to pitch around 0.75 million cells of viable yeast, for every milliliter of wort, for every degree Plato, for an ale- according to mrmalty.com.

From that site:
(0.75 million) X (milliliters of wort) X (degrees Plato of the wort)
There are about 3785 milliliters in a gallon. There are about 20,000 milliliters in 5.25 US gallons.
One degree Plato is close to 1.004 of specific gravity (SG). Just divide the decimal portion of the SG by 4 to get the approximate degrees Plato (e.g., 1.060 is 15°P).
The proper amount of yeast for 5.25 US gallons of 1.060 wort is around 225 billion cells if you are pitching 0.75 million per milliliter.
(750,000) X (20,000) X (15) = 225,000,000,000

Another way to put it, you need about 3 3/4 billion cells for each point of OG when pitching into a little over 5 gallons (20 liters) of wort. Double that number for a lager.

So, the math here would be: (750,000) x (20000) x 27 = 405,000,000,000

I didn't look at the calculator, but it seems that the math here is different than the calculator results you got.

I would say you'd need four packs for a proper pitching rate, if the yeast is fairly fresh.

In any case, I wouldn't assume that underpitching a higher OG wort is any "better" than underpitching a smaller OG wort, which seems to be your question. Underpitching is underpitching. I think that more esters are created by the stressed yeast so in a Belgian it might be much more acceptable.
 
Yeast count is one of those topics that most average brewers go ape crap about if it doesn't match their computer programs' exact numbers. Even the experts can't agree on exactly how much to pitch all the time.

The idea is to try your best to get an appropriate number of good healthy yeast in wort. They will reproduce to the level that is prefect for your beer. 2 vials will get you close enough to your goal that you should not have to worry about off flavors and such. It may have a bit longer lag time than say a larger starter or 3 vials.

As far as when to use a starter, IMHO every time you brew you should make a starter. Not so much for cell count, but for yeast viability. It's important that the yeast be healthy and ready to go when pitched. This will is often overlooked by many brewers who are just worried about the number of cells they pitch.

Also unless you have lab to sample the yeast and count the cells, you are just geusstimating how many your pitching no matter what or how you prepare them.

The bottom line is, get within a good ballpark estimation of how cells you're pitching. Programs like Mr Malty can be a great aid in this, but remember if they are not counting your yeast for you. Everytime you pitch do so with the best yeast you can.
 
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