PDA

View Full Version : Show Mead with dead yeast as nutrient



dr9
04-07-2010, 12:20 PM
At what point and what quantity should I add boiled yeast (Fleischmann's) to a 1 gallon batch of show mead with 2.5 pounds of various leftover honey using red star p cuvee or EC-1118 (haven't decided yet)?

Is it against the rules to rehydrate the yeast with go-ferm?

Thanks!

AToE
04-07-2010, 12:30 PM
Is it against the rules to rehydrate the yeast with go-ferm?

Thanks!

Yup, breaks the rules.

wayneb
04-07-2010, 12:59 PM
To answer your first question, since all the nitrogen sourced by the boiled yeast is amino nitrogen (and readily used by the living yeast, without being toxic to them), you can add your yeast-based nutrient right as you pitch your rehydrated live yeast.

And the reason that GoFerm "breaks the rules" for show meads, is that it is processed to contain higher concentrations of some nutrients than are found naturally in boiled yeast.

akueck
04-07-2010, 01:04 PM
For a show mead, would it make sense to simply pitch a huge biomass of yeast? Very low nutrient requirements if the yeast population is fairly stable....

dr9
04-07-2010, 01:14 PM
Right, I'm doing the big biomass thing. I am mainly interested in the amount of dead yeast to use as nutrient. A teaspoon? A cup? I have no idea.

Medsen Fey
04-07-2010, 05:45 PM
Be careful with the large biomass approach. According to Linda Bisson in Am. J. Enol. Vitic., Vol. 51, No. 2, 2000.




We have also seen that a very high yeast inoculum(10^8 cells/mL, equivalent to 40 lb active dry yeast/1000 gal) results in a sluggish fermentation. These fermentations initiate very rapidly, but seem to progress slower than fermentations that build a population of yeast rather than starting at maximal cell density. These fermentations display greatly elevated levels of yeast esters. The attempt of a large number of cells to absorb a limited amount of nitrogen may lead to a deficient cell status in the whole population that only manifests itself during stationary phase.




That's a bit less than 5 grams per liter. I have successfully used the large biomass approach (see the HotMead yeast test in the Patron's Brewlogs for an example). It can work, but be aware; I had not read this before. I'll probably be jinxed now and it will never work again for me (and now you're jinxed too :p ) .

We really need to test the YAN concentration provided by brewer's yeast. I have done it estimating it to be similar to yeast hulls in the past (8 ppm for 1 gram in a gallon) and that worked okay with no funky flavors despite the large amount. It was kind of yeasty, but that aged out.

wayneb
04-07-2010, 06:27 PM
I've had success in keeping "moderate" nitrogen needing yeast from going stinky by using a 12.5 ppm per gram per gallon estimate of the YAN available from dried brewer's yeast (the dead stuff from health food stores), and dosing up to an equivalent 225 ppm YAN. My musts were also slightly more "yeasty" than those nourished with commercial nutrients, but that smell and flavor also attenuated with aging.

Medsen Fey
04-07-2010, 07:12 PM
I've had success in keeping "moderate" nitrogen needing yeast from going stinky by using a 12.5 ppm per gram per gallon estimate

Your number is probably closer as the whole yeast likely have more nitrogen than the hulls. Do you know a good (i.e. not too expensive) lab we can send some samples to? If not, maybe we can find one and negotiate a GotMead discount; between the whole group we can probably generate as many tests as a small winery.

wayneb
04-07-2010, 10:40 PM
I don't know of one, but Oskaar should. If he doesn't respond directly to this thread in the next day or two, I'll send him a PM (and I'll also query a couple of my winemaker friends).

dr9
04-08-2010, 09:45 AM
I've had success in keeping "moderate" nitrogen needing yeast from going stinky by using a 12.5 ppm per gram per gallon estimate of the YAN available from dried brewer's yeast (the dead stuff from health food stores), and dosing up to an equivalent 225 ppm YAN. My musts were also slightly more "yeasty" than those nourished with commercial nutrients, but that smell and flavor also attenuated with aging.

To make sure I understand you, that seems like alot.

You are talking about 20ish grams per gallon, which is about 3/4 ounce or three Fleischmann's packages (not taking into consideration the whole yeast will have more nitrogen as is currently in discussion).

Is that step feeding, like adding a third at pitch, another at 1/3, and another at 1/2, or just going all-in on the turn card?

Is that correct?

dr9
04-08-2010, 10:00 AM
Page 3 indicates that yeast that has completed fermentation has between 5 and 7% nitrogen content by weight.

http://www.lallemandwine.com/IMG/pdf/Comparison_of_Nitrogen_and_Oxygen_.pdf

dr9
04-08-2010, 10:17 AM
453 grams in a pound. A gallon weighs about 8.6 pounds.

3895 grams of weight in a gallon of must.

1 gram of dead yeast with 5% nitrogen content would be .05 grams of nitrogen.

.05 / 3895 = 0.0000128

Is that 128 ppm? I haven't had a math class in a very long time.

Of course this is all by weight, not volume.

Medsen Fey
04-08-2010, 11:02 AM
That's an excellent piece of information - Nice Find!

I'm not sure if all that nitrogen is yeast assimilable as some might be in the form of proteins. However, if you make the assumption that it is assimilable, and that 6% is the number, then adding 1 gram of yeast to 1 gallon would add about 15 ppm nitrogen.

1 gram is 1000 mg
6% would be 60 mg N (N for nitrogen)
60 mg N/3.8 L = 15.8 mg N/L = 15.8 ppm ____________ mg/L is the same as ppm

There is some further detail on yeast extract HERE (http://www.eurasyp.org/public.levure.extrait.screen).


Main components of Yeast Extract The typical composition of Yeast Extract is (expressed on dry matters basis) :

total nitrogen content : 8 to 12 %, corresponding to a protein content of 50 to 75 %
amino nitrogen content : 3.0 to 5.2 %
total carbohydrate content : 4 to 13 %
lipid content : none or very little.

This would suggest that half the nitrogen is in the form of amino acids that are yeast assimilable.

We really need to send a sample for testing. I'm tired of guessing.

Medsen

dr9
04-08-2010, 11:12 AM
But doesn't boiling it free up some of the nitrogen into YAN?

Medsen Fey
04-08-2010, 11:24 AM
Probably, but I have no idea how much.

dr9
04-08-2010, 11:30 AM
More data:

Yeast is 52% protein.

http://ajplegacy.physiology.org/cgi/pdf_extract/48/2/199

dr9
04-08-2010, 11:39 AM
Wouldn't you know it would be on the last page?

Crystalline pyrophospatase from Fleishmann's yeast is 16.25% nitrogen.

http://jgp.rupress.org/content/35/3/423.full.pdf

Piece by piece we can figure this out...

dr9
04-08-2010, 11:44 AM
Page 4

the debate is over!? 26.8% of nitrogen in fleishmann's yeast is amino nitrogen.

http://www.jbc.org/content/52/1/91.full.pdf

wayneb
04-08-2010, 11:53 AM
I'm with you, Medsen - too much guessing, and not enough data. To further muddy the waters, remember that although active dry yeast may be 52% protein by weight, that doesn't necessarily correlate to half of the nitrogen in yeast being trapped in unassimilable proteins. Additionally, part of autolysis is proteolysis, where some of the proteins in the cells slowly break down into amino constituents. SO... what you get from "brewer's yeast" that has been partially autolyzed in processing, may be significantly different from the YAN obtained by boiling "fresh" active dry yeast.

We clearly need to make up several samples of alternative "natural" nutrients, and have them properly assayed, before we can come to any definitive conclusions.

At least from what people have thus far uncovered here, my assumption of 12.5 ppm per gram per gallon (which was "gut feel" arrived at from an extrapolation of what is currently available from a number of commercial yeast nutrient products), isn't too far off the mark. ;D

Medsen Fey
04-08-2010, 12:04 PM
Some further data that seems to agree with the roughly 50% YAN number can be seen in this study (http://www.bionewsonline.com/b/2/h_gaudreau_02.htm). They were looking at the effect of various yeast extracts (and filtrates) on lactobacillus growth. Extracts were provided by companies including Red Star and Lallemand.

Interestingly the extract from Baker's yeast tends to have higher total nitrogen than the Brewer's yeast (more like 10-12%). You might get more goodie out of Fleischmann's than brewer's yeast.

Medsen Fey
04-08-2010, 12:25 PM
Page 4

the debate is over!? 26.8% of nitrogen in fleishmann's yeast is amino nitrogen.

http://www.jbc.org/content/52/1/91.full.pdf

I LOVE ancient studies!
All these other studies suggest something closer to 40-60% of the nitrogen is amino in yeast extract. That is significantly higher than the 26.8% number they got.

What ever the true number is, clear it is relatively low and large amounts of yeast must be used to provide enough nutrient for an active fermentation.

If someone can help identify a cheap lab, I'm ready to send some samples. Anyone here need a science project for school?

dr9
04-08-2010, 03:47 PM
My GF is in organic chemistry class now, and taking part two next semester. I already asked her if she could determine such things, and I was laughed at, out loud, a few hours ago. I bet one of her TA's might be interested though, if there was money involved.

dr9
04-08-2010, 03:50 PM
Medsen, remember in that study they said 68% were "undeterminable"... so the results of the ancient vs modern are not necessarily contradictory.

dr9
04-08-2010, 04:53 PM
If Oskaar doesn't chime in soon, I'm going to throw a pillowcase of kittens into the Oconee River.