Pro brewery pitch rates vs. homebrew "overpitching"?

[emjay]

That's why they dump the trub.

Yes, but the fact it even collects there at all indicates that a lot of the fermentation is taking place under a great deal of pressure. Heck, those conicals are so tall that the yeast doesn't even need to be on the bottom to be under a lot of pressure.

And in fact, pressure is something that can be tweaked to produce different results. Higher pressure = reduced esters. So I simulate a tall(er) conical with my blow-off tube in various depths of sanitizer. And with certain beers (like my saison), I don't even use an airlock, but rather just aluminum foil - and this was actually even recommended by Jamil.

 

[Malticulous]

Mr. Malty spits out 1.5 million cells x Degrree Plato/ml for lagers. Everything I've read suggests closer to .8 on commercial lager operations and I have personal success at that rate. Proper oxygen levels are every bit as important.

Personalty I think over/under pitching is any amount that dosen't get the desired results, be it culture longevity, fermantation rate or desirable esters. Using fixed numbers is giving up one of the few controls we have over yeast.

 

[AdamWiz]

Personalty I think over/under pitching is any amount that dosen't get the desired results, be it culture longevity, fermantation rate or desirable esters.

I think this probably says it best. I mean, if I pitch 3/4 of the recommended amount and get the results I want, who's to say I underpitched? If I pitch twice the yeast and get favorable results, who's to say I overpitched? It's only underpitching if you don't get the results you want. When I say that Mr Malty's recommendations seem excessive sometimes, I don't mean that their suggestions are too much yeast. I'm just saying that a lot of the time, basically the same results can be had without pitching as much. I believed for far too long that I would never get good fermentations unless I made huge starters. Then one brewday, I realized that I had never made a starter the day before as planned. I just pitched a single WL vial(WLP001) into 5 gallons of 1.058 wort(Amber ale), and guess what? No different than the other 2 times I had made the same beer with starters. If I can pitch less and get the same results, why wouldn't I?

 

[emjay]

Ideal rates are based on the only real objective measure there is - continued yeast health. How one decides to tweak it from there is up to the brewer.

I don't know how big your starters were, but I guarantee you that it wasn't the exact same when you pitched just a vial.

Close enough? Probably, but if you tasted them side-by-side, I assure you that you would notice the difference (assuming your palate doesn't suck, of course).

 

[Malticulous]

What do you mean by "ideal rates." Lagers and ales see the same yeast growth with the same rates, oxygen and nutrients. 1.5^6xPlato/ml is pushing past ideal yeast growth that I would think is at least two buddings.

 

[Malticulous]

You know what I'd like to see? An experiment. One 10 gallon batch, even divided between two fermenters. One would be underpitched, like using one vial in a 1.065 batch. The other, overpitched. We'd have to calculate what that is, but say 4 vials as an example. All else would remain the same- temperature, time in the fermenter, etc. At the end of 10 days, check the SG and have a blind taste test. Bottle (or keg) and have another taste test in 3 weeks.

I'm unwilling to do it for two reasons- one, I refuse to underpitch even in the interests of science and two, I would say to avoid a starter to take out the possiblity of contamination or any other variable, and I don't want to spend that much money on yeast!

But I think it would be the only way to say what the effects of underpitching vs overpitching the same batch in homebrewing do.

Saun Torell did a simple test. Temp was not consistent and many missing variables (or hard to find.)

Yeast Pitching Rate Results « SeanTerrill.com

Recipe formulation could compensate for most of the noted changes.

while the beers almost certainly are different, there is no consensus about which is better. Simply put, nearly half of people prefer under-pitched beers.

Oddly enough--that's not his conclusion.

 

[a10t2]

Oddly enough--that's not his conclusion.

As I said later on, I think it's justifiable to discount the preferences of tasters who can't differentiate the two beers. That said, I wanted to clearly distinguish my interpretations from the actual data. Obviously you can disagree with my conclusions.

If you have questions about any "missing variables", let me know and I'll do what i can to address them.

Sean

 

[AdamWiz]

One thing I don't understand is, why do White Labs and Wyeast advertise their products as being the proper amount to directly pitch into 5 gallons when the actual recommended pitching rates are significantly higher? Seems to me that a homebrew supplier would want to make sure that the product they are selling will deliver the best possible results when used as directed. I know White Labs mentions making a starter on their label, but it doesn't say that it is necessary or even recommended. They just say something like "if desired, a starter can be made". Why not make bigger vials?

 

[samc]

Even with bigger vials you would still run into the potential problem of age, poor handling, etc. and therefore making a starter would still be called for. You can certainly pitch those vials into a small beer with great results and even get "beer" with a larger OG, but in the end a starter works best in most cases. As to the concern about advertising the products, I'd have to agree that they don't really hit the brewer in the face with BOLD print telling you to do a starter.

I agree with those that question the Mr Malty pitching rates. I generally don't go with the recommendations to the full extent. For a 6 gallon batch even when it calls out for 2 vials, I just do a larger single no-step up starter and have had great results that way.

The subject of pro vs. home brew pitch rates is certainly one that I'd love to know the real answer to, I'm staying tuned in.

 

[AdamWiz]

The subject of pro vs. home brew pitch rates is certainly one that I'd love to know the real answer to, I'm staying tuned in.

I think that pro brewer's large pitching rates are mostly to increase fermentation speed and for the viability/repitchability of yeast with constant multi-generation use. Their main concerns are getting beer through the fermenters quickly and making sure their yeast is not stressed at all so they can continually reuse it. These 2 things are not nearly as important to homebrewers who don't need to rush production to make money and don't need to worry about cost cutting as much by repitching for many generations. For a pro brewer though, it is VERY important to be able to extensively reuse yeast to cut costs. They can't just buy a 6$ White Labs vial like us. I only reuse yeast from my lightest and lowest gravity beers, and even then for only a couple generations. I would rather spend an extra 6 bucks than risk mutated, contaminated, or overly stressed yeast messing up a batch.

 

[Malticulous]

Thanks for the work Saun.

Pitching more than .8 to 1 million per degree plato/ml has little increase in fermentation rate, and pitching much more than that reduces yeast growth. 10 to 12 million/ml is the sweetspot.

The actual pitching rate used varies considerably between breweries and rates of 5 to 20 million cells/ml of wort are common depending on the specific gravity of the wort. An optimum level is considered to be 10 to 12 million cells/ml and this should result in a reproduction rate for lager yeast of 3 to 5 times.

This is 15P wort.

 

[Brewerforlife]

I think that pro brewer's large pitching rates are mostly to increase fermentation speed and for the viability/repitchability of yeast with constant multi-generation use. Their main concerns are getting beer through the fermenters quickly and making sure their yeast is not stressed at all so they can continually reuse it. These 2 things are not nearly as important to homebrewers who don't need to rush production to make money and don't need to worry about cost cutting as much by repitching for many generations. For a pro brewer though, it is VERY important to be able to extensively reuse yeast to cut costs. They can't just buy a 6$ White Labs vial like us. I only reuse yeast from my lightest and lowest gravity beers, and even then for only a couple generations. I would rather spend an extra 6 bucks than risk mutated, contaminated, or overly stressed yeast messing up a batch.

This is right on!!!

 

[Brewerforlife]

Thanks for the work Saun.

Pitching more than .8 to 1^6/ml per degree plato has little increase in fermentation rate, and pitching much more than that reduces yeast growth. 10^6/ml into 12P or 12^6/ml into 15P wort is in the sweetspot.



This is 15P wort.

This is also!!!