# A I Over Pitching?

Making a Double IPA today OG: 1.084.

I made a 2L starter of from slurry of US-05. Into the flask I pitched two mason jars of harvested yeast. Each jar was about 1/6 of the way full of yeast.

I used the pItching rate calc on MrMalty and it says that I need 181 ml of yeast. But that seems way low to me.

Am I about to pitch way too much yeast?

On an unrelated note… I made the starter on Friday night, let it sit on a stir plate for 24 hours and then popped it in the fridge. Typically, by now all of my yeast will have floculated to the bottom and the separation between beer and yeast will be very clear. But in this starter, it’s still very cloudy and the beer is still bubbling like crazy. I’m guessing this is a symptom of the amount of yeast that went into it?

I’m no starter expert. Only made a handful myself but that sounds like a lot. My recent starter from harvested yeast I used roughly 4 tablespoons in a 1L that I stepped up to 2L. I got that scientific measure of yeast from Nighthawk in the thread below:

viewtopic.php?f=26&t=116364

Chris, the info you give is incomplete. Mason jar: what size? 1/2 pint, pint, quart, 1/2 gallon?

Assuming using quart jars, 1/6th is ~5.3 oz (32/6=5.33)

181ml is ~ 6.1oz http://www.onlineconversion.com/volume.htm

Mr Malty’s yeast requirement is based on the age of the yeast. When was the yeast harvested?

Using the “re-pitch from slurry” tab, my understanding it that is a direct pitch calculator. No starter is needed. In this scenario, I would have pitch 1 jar and called it good. If the yeast was 3-4 weeks old.

Things to consider.

WYeast/White Labs state that there is approximately 100B cells in there products.

Using Mr Malty, we can gauge how much yeast is in a slurry. From that, you can approximate how much slurry to use in a starter to replace 1 or 2 packs of yeast.

But, according to Woodlandbrew

, Mr Malty’s (and yeastcalc) viability calculator is overly conservative.

As for the starter being cloudy, adding a larger amount of yeast should have caused a shorter fermentation. Opposite of what you are seeing. Something else is going on.

Use Mr Malty/yeastcalc as a guide. But not as a hard rule. And, don’t take anything I say as a hard rule either. It’s just my interpretation of things. And what seem to work for me.

I’m using quart jars.

[quote=“Nighthawk”]

Mr Malty’s yeast requirement is based on the age of the yeast. When was the yeast harvested? [/quote]
Harvested back in Jan.

[quote=“Nighthawk”]
Using the “re-pitch from slurry” tab, my understanding it that is a direct pitch calculator. No starter is needed. In this scenario, I would have pitch 1 jar and called it good. If the yeast was 3-4 weeks old. [/quote]
I was under the impression that it’s a good idea to make a starter from slurry just to make sure that the yeast you have in the slurry are still healthy and active.

Thanks for the input. I ended up pitching about 1600 ml of the 2l starter. Strange thing happened though when I pitched… I got a ton of foam building up as I poured the starter in. So much so, that it was bubbling up out of the carboy and I hate to wait for the foam to die down each time I poured in a bit of the starter. I’m wondering if this is because I did not decant the starter and instead poured the whole mixture straight into the fermenter.

Anywho - we’ll see what happens. Thanks for the insight.

I doubt you over pitched. For a double IPA you want all the yeast you can get in there. If you did over pitch, it won’t be a bad thing like under pitching would be.

Actually, you’ll get a lot more ester production from over-pitching than you will from under-pitching.

Actually, you’ll get a lot more ester production from over-pitching than you will from under-pitching.[/quote]
But he’ll likely have better attenuation from slightly over pitching versus under pitching, which is what you want in a double IPA.