Author Topic: Yeast Nutrient  (Read 4249 times)

Offline charles1968

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Re: Yeast Nutrient
« Reply #30 on: December 23, 2015, 08:53:05 PM »
After this presentation, I started using nutrients. There was discussion of Zinc in here, and also in a presentation by MaryBeth Raines.

http://www.ahaconference.org/wp-content/uploads/presentations/2009/Tobias-Fischborn-NHC2009-Yeast%20nutrition.pdf

I hope this helps.

Interesting presentation. There does seem to be a case for adding nutrients such as zinc to high gravity beers, beers made with fussy yeasts, and maybe lagers. I'm not convinced about free nitrogen. Malt contains a lot of amino acids. If the yeast has to work a bit harder to get it, and that slows down fermentation a little, that may be no bad thing. Stimulating faster fermentation in normal wort isn't necessarily a good idea. 
« Last Edit: December 23, 2015, 08:55:12 PM by charles1968 »

Offline HoosierBrew

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Re: Yeast Nutrient
« Reply #31 on: December 23, 2015, 09:17:23 PM »
If the yeast has to work a bit harder to get it, and that slows down fermentation a little, that may be no bad thing. Stimulating faster fermentation in normal wort isn't necessarily a good idea. 


I don't know. Getting a strong, quick start to out-compete potential microbes and not stressing your yeast to take in enough nutrients by giving them the nutrients abundantly seem to be solid yeast practices to me. Many strains are known to throw higher levels of esters and off flavors/aromas when stressed. To each his own.


EDIT - Not saying you can't make good beer without nutrient - of course you can, especially on an average strength beer. But there's an abundance of info (NHC presentation included) that adding nutrient is beneficial for yeast.
« Last Edit: December 23, 2015, 09:28:50 PM by HoosierBrew »
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Offline charles1968

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Re: Yeast Nutrient
« Reply #32 on: December 23, 2015, 09:54:33 PM »
If the yeast has to work a bit harder to get it, and that slows down fermentation a little, that may be no bad thing. Stimulating faster fermentation in normal wort isn't necessarily a good idea. 


I don't know. Getting a strong, quick start to out-compete potential microbes and not stressing your yeast to take in enough nutrients by giving them the nutrients abundantly seem to be solid yeast practices to me. Many strains are known to throw higher levels of esters and off flavors/aromas when stressed. To each his own.


EDIT - Not saying you can't make good beer without nutrient - of course you can, especially on an average strength beer. But there's an abundance of info (NHC presentation included) that adding nutrient is beneficial for yeast.

Raising the temperature also gets yeast off to a good start but that doesn't make it necessarily good practice. Given the choice, yeast would rather ferment at 90F or more, but good beer is made by keeping activity restrained. Slow and steady is better than fast and furious.

Offline charles1968

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Re: Yeast Nutrient
« Reply #33 on: December 23, 2015, 10:32:16 PM »
Here's a relevant page from Yeast by Chris White and Jamil Zainasheff:

Quote
An all-malt wort contains all the nutrients yeast need for fermentation except oxygen and zinc. Adjuncts such as corn, rice, or sugar syrups do not contain many essential nutrients such as nitrogen, minerals, and vitamins. Even with all-malt worts, brewers may find advantage in adding nutrients to improve and fine tune fermentation performance. Several yeast nutrient products available provide a balanced source of nitrogen, minerals, and vitamins. Brewers can also add specific nutrients individually, but keep in mind that excessive amounts of nutrients can also cause problems. Your goal is to find the optimal balance for your fermentation conditions.

Nitrogen makes up about 10 percent of the dry weight of yeast cells. The nitrogen in brewer’s wort is mostly in the form of amino acids. There are twenty different types of amino acids, and yeast can either make the amino acids they need or assimilate them from the wort. Both wort amino acids and inorganic nitrogen supplements affect flavor, which may be good or bad depending on your goals.

Similar to how yeast approach different sugars, yeast assimilate and utilize wort amino acids as rapidly and efficiently as possible. Yeast take up and utilize some wort amino acids (Group A) within the first day, while others (Group B) are taken up gradually throughout fermentation. Yeast do not take up some others (Group C) until after a substantial lag. And yeast do not utilize the most abundant amino acid in wort, proline (Group D ), at all. The specificity of permeases that transport amino acids across the plasma membrane control the utilization rates. The fastest way for yeast to utilize nitrogen is through transamination. In this process, a donor amino acid gives up its alpha-amino nitrogen to the keto acid to form the desired amino acid. Therefore, for the most part, wort amino acids are converted to alpha-keto acids. This is why yeast do not utilize proline, because it is the one amino acid where the alpha-amino group is a secondary amine (bound to two carbons) and cannot be transaminated.

This process has profound implications for flavor. The alpha-keto acids formed are decarboxylated to form an aldehyde, which is subsequently reduced to alcohol, and this is the source of fusel alcohols. This is why amino acid supplements can affect the quantity and type of fusel alcohol formed. In addition, changes in the fusel alcohol profile affect the ester profile. This is one reason why amino acid supplements are not necessarily superior to inorganic nitrogen.

Offline charles1968

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Re: Yeast Nutrient
« Reply #34 on: December 23, 2015, 10:44:29 PM »
This is from Mary Beth Raine's article:

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The addition of yeast nutrients and certain salts can also improve yeast growth and are a worthwhile addition to starters.  Yeast nutrients usually are of two types, one which is ammonium phosphate-based, and the other which is amino acid/peptide and vitamin-based (similar to the peptone and yeast extract in the laboratory media described below).  Both serve the same basic function which is to increase the nitrogen content of the wort and yeast.  A mixture of different nitrogen sources have been shown to enhance both growth and fermentation and suggest that the amino acid/peptide-based nutrients may be more appropriate than diammonium phosphate.  Also rapidly growing yeast such as those in starters have a higher than normal nitrogen requirement.  Thus starter worts should be supplemented with yeast nutrients so that nitrogen is not limiting.
 
Ammonium phosphate-based nutrients impart very little to the flavor profile.  The same is not true of the amino acid based extracts which tend to impart an autolyzed flavor (bloody, bouillon-like, and metallic) if used in excess (greater than a Tablespoon per 5 gallons).  Thus amino-acid based nutrients should be used sparingly (if at all) in the fermenter.  This is an important consideration when making meads since honey is very low in nitrogen and delicate in flavor.  Therefore diammonium phosphate is the preferred nutrient in meads although a small amount of the vitamin/amino acid-based extract should be added ( 1 tsp) to provide additional vitamins and minerals.
 
We have recently tested the effects of a variety of food-grade amino acid/peptide-based nutrients on yeast growth (Figure 2).  These experiments indicate that the addition of certain yeast nutrients (especially nutrients #3 and 4) can increase the rate of yeast growth but not the overall concentration or yield of yeast.  Thus the addition of yeast nutrient to starters can help accelerate their growth.  This is important for homebrewers since we rarely sterilize our worts and rapid growth is necessary for the yeast to take it over the starter before any potential bacteria can grow.  Unlike the fermenting beer,  yeast nutrients can be added at relatively high concentrations (1% or about 1/4 tsp per quart) to starters since flavor is not an issue. If you are worried about the flavor of the starter contributing to your beer flavor, you can always let the yeast settle and decant off the majority of the liquid.

Offline hopfenundmalz

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Re: Yeast Nutrient
« Reply #35 on: December 23, 2015, 10:53:21 PM »
There are the stories one hears about the all SS breweries in Germany, that have a section of Zinc piping.

As far as fermentation speed goes, my lager fermentation times now that I use nutrients, proper pitch rates and O2, are in the 5-6 day range, which is what the 2 German Brewers I talked to on the respective tours said they experience. Whenever I read of a Homebrewer doing a standard lager, and the fermentation has been going on for 2 weeks, well I try and help.

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Offline charles1968

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Re: Yeast Nutrient
« Reply #36 on: December 23, 2015, 10:58:38 PM »
There are the stories one hears about the all SS breweries in Germany, that have a section of Zinc piping.

As far as fermentation speed goes, my lager fermentation times now that I use nutrients, proper pitch rates and O2, are in the 5-6 day range, which is what the 2 German Brewers I talked to on the respective tours said they experience. Whenever I read of a Homebrewer doing a standard lager, and the fermentation has been going on for 2 weeks, well I try and help.

Lagers do need a bit of an extra push.

Offline charles1968

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Re: Yeast Nutrient
« Reply #37 on: December 23, 2015, 10:59:47 PM »
Another long but hopefully interesting quote, this time from the Wikipedia entry on "yeast assimilable nitrogen"

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Yeast assimilable nitrogen or YAN is the combination of Free Amino Nitrogen (FAN), ammonia (NH3) and ammonium (NH4+) that is available for the wine yeast Saccharomyces cerevisiae to use during fermentation. Outside of the fermentable sugars glucose and fructose, nitrogen is the most important nutrient needed to carry out a successful fermentation that doesn't end prior to the intended point of dryness or sees the development of off-odors and related wine faults. To this extent winemakers will often supplement the available YAN resources with nitrogen additives such as diammonium phosphate (DAP).[1]

However, the addition of excessive amounts of nitrogen can also create a hazard as other organisms besides beneficial wine yeast can utilize the nutrients. These include spoilage organisms such as Brettanomyces, Acetobacter and Lactic acid bacteria from the Lactobacillus and Pediococcus genera. This is why many wineries will measure the YAN after harvest and crushing using one of several methods available today including the nitrogen by o-phthaldialdehyde assay (NOPA) which requires the use of a spectrometer or the Formol titration method. Knowing the YAN in the must allows winemakers to calculate the right amount of additive needed to get through fermentation, leaving only "nutrient desert" for any spoilage organisms that come afterwards.[2]
« Last Edit: December 23, 2015, 11:02:01 PM by charles1968 »

Offline HoosierBrew

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Re: Yeast Nutrient
« Reply #38 on: December 23, 2015, 11:03:32 PM »
Raising the temperature also gets yeast off to a good start but that doesn't make it necessarily good practice. Given the choice, yeast would rather ferment at 90F or more, but good beer is made by keeping activity restrained. Slow and steady is better than fast and furious.


Well of course fermenting @ 90F is a bad practice !  Using proper temp control (and therefore controlling yeast derived off flavors/aromas) has zero in common with trying to restrain yeast activity by not using nutrient. I don't propose using more than the amount recommended by Wyeast, or that you use it at all for that matter. Just saying that there is evidence posted by others in the field (NHC presentation posted) that nutrient can be beneficial in limiting sulfur and for general yeast health and performance. YMMV.
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Offline charles1968

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Re: Yeast Nutrient
« Reply #39 on: December 23, 2015, 11:39:56 PM »
Agreed. I think there are pros and cons to using it in the main wort but it's clearly handy for starters.

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Re: Yeast Nutrient
« Reply #40 on: December 24, 2015, 01:02:03 AM »
I add nutrient to my starter wort, but I do not add it to my beer wort.  I use MYGP (Malt extract, Yeast extract, Glucose, Peptone) that I prepare for solid media.  I can attest to the bullion-like smell of amino acid-based nitrogen sources.  Peptone is made via the hydrolysis of protein into its constituent amino acids.  I use a soy-based peptone known as soytone when I prepare MYGP.  Peptone is also known as protein hydrolysate.  Unlike the hydrolysis of starch and sugar, the hydrolysis of protein requires a positive hydrogen ion in addition to a water molecule to break a peptide bond.  Like a glycosidic bond, a peptide bond is the result of a condensation reaction.

Offline narcout

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Re: Yeast Nutrient
« Reply #41 on: December 24, 2015, 05:25:48 PM »
I came across the thread below awhile ago where someone stated they contacted Wyeast about the composition of their nutrient blend:

http://www.homebrewtalk.com/showthread.php?t=334882

Per 1/2 teaspoon in 5 gallons:

Calcium 0.696 ppb
Magnesium 0.928 ppm
Sulfate 13.920 ppm
Zinc 0.635 ppm
Manganese 0.567 ppm
Thiamine 0.241 ppm

Further down in the thread (post #6), someone listed the minerals they found when analyzing a sample of Wyeast nutrient in an X-ray diffractometer.
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Offline jjflash

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Re: Yeast Nutrient
« Reply #42 on: December 25, 2015, 06:54:37 PM »
So why does Wyeast recommend dissolving in warm water before pitching in wort?
I bet most, like me, toss it directly into the boil.
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Offline majorvices

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Re: Yeast Nutrient
« Reply #43 on: December 25, 2015, 07:01:19 PM »
So why does Wyeast recommend dissolving in warm water before pitching in wort?
I bet most, like me, toss it directly into the boil.

I think just to keep it from clumping up and not fully dissolving. I started dissolving mine recently.

Offline JJeffers09

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Re: Yeast Nutrient
« Reply #44 on: December 28, 2015, 06:01:03 PM »
I dissolve mine in warm water, there are larger chunks that need a good break up with a spoon, and you will see a little foaming action in warm water.  To me it is like hydrating dry yeast before using it in the recipe for bread or pitching into beer.  If proofing bread you will eventually see the yeast start to blow up if not rehydrated in warm water, but it wont be evenly distributed throughout the dough (probably not the best description but meh it works).  So I just assume breaking it up in 2:1 ratio water:energizer/nutrient is just enough to help it dissolve in the wort.
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