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Denny · 08-19-2012, 03:52 PM

Quote:

Originally Posted by jholen

Ah, maybe I misunderstood the two of them.

No growth required = lots of esters? ie. more flavor in that regard.

Yep.

jholen · 08-19-2012, 11:32 PM

Quote:

Originally Posted by Denny

Yep.

Thanks for clarifying Denny!

**TopherM** · 08-20-2012, 04:07 PM

I've heard many experts say that 10-15 years ago, it was much easier to produce consistent strains of liquid yeast than it was dry yeast. Today, however, dry yeast are every bit as consistent as liquid yeast.

If you don't go through the proper procedures to control pitch rates with liquid yeast starters, you are MUCH better off just pitching dry yeast, as a single packet of dry yeast has a viable cell count for a 5-10 gallon batch, whereas just pitching a single vial of liquid yeast is usually WAYYYY underpitching, shocking and overworking the yeast.

So, there is no arguement that it is better to use liquid yeast if you are calculating pitch rates and making proper starters, but if you ARE NOT your beer will likely be better with dry yeast, and your wallet will thank you for it!!!

**osagedr** · 08-20-2012, 04:36 PM

Quote:

Originally Posted by KISS Brew

This is a fact. I've split a batch between US-05 and Wyeast 1056, and I didn't perceive a difference.

Me too, in an APA. Both turned out really well. I generally use liquid if I have the time to do a starter, but have zero problem rehydrating dry yeast and pitching it. Either way, I will expect better beer to be made from the slurry that results.

**BrewKnurd** · 08-20-2012, 04:47 PM

Quote:

Originally Posted by Denny

It's actually the other way around. The same enzyme, acetyl co-A, is used for both cell growth and ester production. when it's doing one of those, it doesn't do the other. So, if you overpitch, there's no need for cell growth and the enzyme produces esters. If you underpitch, the enzyme goes to cell growth and you get less esters. This is to some degree dependent on yeast strain, but in general that's how it works.

Interesting, this is the first time I've heard this. I've always gone with what Wyeast and white labs have on their sites, which is the opposite, that low pitch rates result in more esters: http://www.wyeastlab.com/com-pitch-rates.cfm and http://www.whitelabs.com/beer/homebrew_FAQ.html

To further complicate, I did find a paper from the Journal of the Institute of brewing that showed that overall ester production had something of a U shape, with high points at the highest and lowest pitching rate, and lower values for intermediate rates. One specific ester, isoamyl acetate, showed a significant drop in production from the lowest pitching rate to the highest.

In summary, this stuff is complicated.

**Shooter** · 08-20-2012, 04:55 PM

US-05 can sometimes add a subtle stone fruit flavor to a beer. To me, it seems like apricot. I haven't normally gotten that with WLP001 or 1056. In certain hoppy beers, I actually think it complements the hops. In bold flavored beers it's subtle enough that I don't really notice it. I use it and S-04 pretty regularly, along with Nottingham. If I was doing something with a very delicate flavor, I might look to one of the liquid yeasts.

Denny · 08-20-2012, 07:19 PM

Quote:

Originally Posted by osagedr

Me too, in an APA. Both turned out really well. I generally use liquid if I have the time to do a starter, but have zero problem rehydrating dry yeast and pitching it. Either way, I will expect better beer to be made from the slurry that results.

Me, too, and I could perceive a difference. A small difference, but the 05 was definitely fruitier.

Denny · 08-20-2012, 07:34 PM

Quote:

Originally Posted by BrewKnurd

Interesting, this is the first time I've heard this. I've always gone with what Wyeast and white labs have on their sites, which is the opposite, that low pitch rates result in more esters: http://www.wyeastlab.com/com-pitch-rates.cfm and http://www.whitelabs.com/beer/homebrew_FAQ.html

To further complicate, I did find a paper from the Journal of the Institute of brewing that showed that overall ester production had something of a U shape, with high points at the highest and lowest pitching rate, and lower values for intermediate rates. One specific ester, isoamyl acetate, showed a significant drop in production from the lowest pitching rate to the highest.

In summary, this stuff is complicated.

Isoamyl acetate, which gives hefeweizen the banana flavor, is one of the exceptions. Generally, hefe yeasts are "exempt" from the rule for some reason. I fist heard the info from Dr. Clayton Cone of Lallemand many years ago. http://www.danstaryeast.com/articles/yeast-growth . At NHC in Seattle this summer, Neva Parker of WhiteLabs said the same thing. If you're an AHA member, you can her presentation here http://www.homebrewersassociation.org/attachments/presentations/audio/2012/1616-08%20Fermentation%20Mythbusters%20-%20Neva%20Parker.mp3

**BrewKnurd** · 08-20-2012, 08:19 PM

Quote:

Originally Posted by Denny

Isoamyl acetate, which gives hefeweizen the banana flavor, is one of the exceptions. Generally, hefe yeasts are "exempt" from the rule for some reason. I fist heard the info from Dr. Clayton Cone of Lallemand many years ago. http://www.danstaryeast.com/articles/yeast-growth . At NHC in Seattle this summer, Neva Parker of WhiteLabs said the same thing. If you're an AHA member, you can her presentation here http://www.homebrewersassociation.org/attachments/presentations/audio/2012/1616-08%20Fermentation%20Mythbusters%20-%20Neva%20Parker.mp3

In looking at the Clayton Cone bit, I'm wondering if one of the key things is: "Anything that inhibits or slows down yeast growth usually causes an increase in ester production: low nutrient, low O2. It has been noted that a drop in available O2 from 8 ppm down to 3 ppm can cause a four fold increase in esters."

Say you have a high pitch rate. Less O2 and nutrients are necessary for the replication phase, because there's just less replication required. Meanwhile, if you have a low pitch rate, more of both are required, and perhaps that makes it more likely that you get into an area where yeast growth slows due to limited O2 or nutrients, thereby causing the increase production of esters?

Just thinking out loud. Will listen to Neva's talk when I'm back home.

**Devin** · 08-20-2012, 08:26 PM

Quote:

Originally Posted by Shooter

US-05 can sometimes add a subtle stone fruit flavor to a beer. To me, it seems like apricot.

I have noticed the same thing. I only have 6 brews under my belt, and I have used 05 for all of them. This flavor that you mentioned is one reason I am going to finally try a liquid yeast out on my next brew.