Pitching rate & flavor

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foxtrot

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In general, is it true that a smaller pitch rate (call it underpitching if you want) will produce more flavor from yeast due to more reproduction? And if you pitch a larger starter, will the beer have a more "clean" flavor?

I just got into making starters and brewed a brown ale using a 2 liter starter with the WLP001 yeast. I brew all-grain and the OG was 1.056, so I followed the MrMalty calculation and supposedly arrived at around 200b cells. The fermentation took off within 6 hours and although everything was "text-book", I think it tastes TOO clean, and lacks some fruitiness I was hoping for. My fermentation temp was 68F. Perhaps I just used the wrong yeast?

Anyway, I'm curious about what kinds of "rule of thumb" everyone has when it comes to making starters. For example, do you make a specific amount of starter for anything less than 1.050 and another for anything over? Do you ever "underpitch" if you want something more fruity/spicy? I'm just speaking of ales at this point. Or... are there so many other factors like temperature, aeration, fermentables, pH etc. etc. etc. that it's just a matter of experimentation and what tastes good to you??? Is it luck???

This is a very nebulus area for me and maybe for other newbies. I tend to like brews that are packed with flavor, so I'm wondering if I'm over-pitching by following examples like MrMalty's calculations, which to me seem a bit much.
 
It's pretty dadgum hard for a homebrewer to overpitch a batch. Chico is a clean yeast, but you can get some nice esters out of it. You just need to ferment a little higher, like maybe 70-72F. That's where I used to ferment Chico, and I liked it.

I've switched to California V/American Ale II from Chico, though. I like its flavor and arom profile more. It's a bit fruitier than Chico, but not to the point of Juicy Fruit. The batch I fermented with WYeast 1332 was a little strong on the bubble gum aroma when I racked it recently, but the flavor is great. I imagine that bubblegum will round out and blend in nicely with the rest of the beer pretty quickly.


TL
 
There are a few yeasts that require a lower pitch rate to produce the correct flavors, for most yeasts and styles starter size only impacts the length of the yeast's growth stage. Trying to control the ester profile with pitch rate is a real dicy approach.

WPL001 is one of the cleanest fermenting liquid yeasts. You might have been better off with WLP004 (Irish).
 
Yes it is true. If you pitch a high count of yeast cells it will reduce the amont of esters produced due to the lowered amount of yeast growth that will accure in your beer.

Can you over pitch? as stated above as a homebrewer that is going to be pretty hard unless you create a starter that was uber massive.

But, with that said, your best bet for ester production is going to be either ferment a bit warmer as david said or use a yeast that produces the estery characters you are after.
 
I think this is a really complicated question, because the ester production from fermenting yeast is dependent on a number of factors:
- yeast strain
- quantity of yeast pitched
- quality (health) of yeast pitched
- temperature at pitching and primary fermentation
- gravity of wort
- oxygen levels in wort
- nutrient levels in wort

To repeat from above, I think the best rule-of-thumb for controlling your ester profile is to always select the correct strain of yeast to match the flavours you want, and pitch healthy yeast at an adequate quantity to well aerated wort. If you follow this approach, you are most likely to obtain the flavour profile you are targetting AND it will be repeatable.

Just as a side note, over-pitching can definitely be a problem for some strains of yeast, particularly those that have a very prominent ester or phenol profile. But like TL says, it is often hard to achieve. Where you tend to hear about over-pitching problems is when people make something like a hefe-weizen by pitching a batch of wort into a primary full of yeast from a previous batcth -- then they complain that this second batch doesn't have the nice fruity and clove-like flavours and aromas that the first one had.
 
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