Yeast Nutrients

So in order to get get a firm grasp on Yeast Nutrients, we need to first understand YAN. YAN stands for Yeast Assimilable Nitrogen - which itself, is comprised of two parts: Primary Amino Nitrogen (PAN) & Ammonia.

Amino Nitrogen content of a must can be determined using the 'NOPA method', while testing for Ammonia levels is done using a ion selective probe (similiar to a pH meter), or an enzymatic test kit. All of this doesnt mean much of yet, as it appears you have to send a sample to a lab for testing (havent found home-use equipment to test for it). So this leaves us, for now, making educated guesses.

The minimum amount of YAN needed to make it through any fermentation is in the 150 - 200 ppm range, although this will mean a lot more when there is a means of testing for it. Upper ranges on YAN can reach 500 ppm. As the alcohol level that one wishes to reach increases, so to does the amount of YAN one must supply. With knowledge that the amount of YAN present in the fruit varies from year-to-year, the need/want to test for those levels, rises just that much higher.

Although YAN can range anywhere from below 150ppm to above 500ppm, some generalizations have been made. A "Low" YAN content is generally something less than ~125 ppm, "Medium" YAN content falling between 125 - 225 ppm, and "High" YAN content being anything over 225 ppm.

There's also been some general recommendations for YAN levels based on Brix readings:


Each yeast strain available on the market, requires a different amount of nitrogen to make it through fermentation without issue & the manufactures of the yeast are having a hard time releasing the YAN requirements for each individual strain, but it's a work in progress. As it sits right now:

Low
71B-1122
Assmanshausen (AMH)
DV10
EC-1118
ICV-D47
K1V-1116
Rhone 4600
QA 23
Uvaferm 43

Medium
BDX
Clos
ICV-D21
ICV-254
MT
RC-212
RP 15
Syrah

High
BA-11
BM-45
BM 4X4
CY3079
ICV-D80
ICV-GRE
W15


Yeast prefer ammonia-based nitrogen, but that's not to say we should be supplying it. When yeast are given the opportunity to feed on ammonia-based nitrogen sources, the yeast population will increase more rapidly due to a 'feeding frenzy'. This does several things, which all reflect on each other; increase in yeast population leads to an increase in internal must temperature, and these factors then lead to excess expulsion of aromatics, and in the end lead to a larger die-off.

Ammonia-based nitrogen sources generate 'spikes' within the fermentation; this was the original thought behind staggering nutrient additions. If one could spread those spikes out, to create a more linear fermentation, then one could also limit the extremes that come along with it.

Organic, amino-based nitrogen sources, are less-favored than ammonia-based sources by yeast, but they are the healthier option. It may only take as little as 1/3 the amount of organic nitrogen (by YAN) to finish the same fermentation as it would with an ammonia/DAP-based nutrient source.

What this means is that the yeast better-utilize the organic amino-based nutrient sources, due to the fact that the yeast have to perform a more-complex set of operations to metabolize this nitrogen. Those 'spikes' seen with ammonia-based nutrients, are instead more 'hill'-like, and this more-complex form of metabolism creates stronger, healthier yeast. Also, yeast will metabolize an amino-based nutrient well past the point where they stop with ammonia-based nutrients.

After about 2/3 of the way through a fermentation, adding additional DAP-based nutrients is only fuel for spoilage organisms; the yeast can't assimilate these ammonia-based nitrogen past that point, no matter how addicted to it they are. They can however, still assimilate organic, amino-based nitrogen forms - although it is still possible to add too much, leaving excess behind for spoilage microbes.

So how do we know how much YAN we're adding, when we add yeast nutrient?
It depends on the nutrient that we use. These are the three that I consider most often:

DAP
YAN Contribution at 25g/hL = 50ppm
YAN Contribution at 30g/hL = 63ppm

Fermaid K
YAN Contribution at 25g/hL = 25ppm
YAN Contribution at 30g/hL = 30ppm

Fermaid O
YAN Contribution at 25g/hL = 10ppm
YAN Contribution at 30g/hL = 12ppm

A hectoliter is 26.41 gallons, so 25g/hL is just-under 1g/gallon.

Another way, is to know the nitrogen content percentage of the nutrient.

DAP = 21%
Fermaid-K = 10%
Fermaid-O = 4%

(X g/L * % ) * 1000 = ppm YAN in g/L

1 gallon = 3.785L
[(Xg/L / 3.785) * % ] * 1000 = ppm YAN in g/gal

X = nutrient amount in g/L
% = percentage of nitrogen content in nutrient

Example:
4% nitrogen in Fermaid-O
1 gram in 1 gallon

[(1/3.785) * .04] * 1000
1 / 3.785 = 0.2642
0.2642 * .04 = 0.01057
0.01057 * 1000 = 10.57ppm YAN

These YAN additions are added to the base assumptions (guesstimates) I mentioned earlier, and coupled together they give you the basis to begin healthy fermentation. It's worth mentioning that the effectiveness of organic nitrogen sources is further enhanced from three-times to up-to four-times that of inorganic nitrogen forms, when yeast are awoken using rehydration nutrients like Go-Ferm.

More about these three nutrient types:

DAP

Pure Di-ammonium phosphate. No added macro- or micro-nutrients. No autolyzed yeast. Should only be used in conjunction with complex yeast nutrients, containing macro- and micro-nutrients. Should never be the main source of nitrogen for a fermentation, and is best-used as a supplement in low-YAN musts. Never add DAP to rehydrating yeast. Never add DAP to a must prior-to or during yeast-pitch.


Fermaid-K

Comprised of inorganic nitrogen (DAP) and organic nitrogen from autolyzed yeast, as well as unsaturated fatty acids and sterols. The unsaturated fatty acids and sterols are important in maintaining yeast's ability to resist alcohol as a toxin, as well as continue sugar-uptake.

Macro Contents

• Diammonium Phosphate
• Amino Acids & Peptides
• Magnesium Sulfate
• Yeast Cell Walls

Vitamins

• Inositol
• Nicotinic Acid
• Thiamin Hydrochloride
• Pantothenic Acid
• Biotin

Trace Elements - Minerals

Recommended dosage: 25g/hL


Fermaid-O

Comprised of organic nutrients from autolyzed yeast & does not contain any DAP or supplemented micro-nutrients. Fermaid-O should always be used in conjunction with a rehydration nutrient, as the rehydration nutrient will supply the needed/missing micro-nutrients for proper yeast health.

Recommended dosage : 40g/hL


So now that we've covered YAN, the ability for yeast to uptake different nutrient types with varying success, how far the levels of YAN in each batch can vary - how does this translate from writing to action?

Staggering nutrient additions has been around the forum for a while - some only add nutrients in 2 stages while some have as many as 6 additions. It's about maintaining those "spikes" or "hills" that you get, using various nutrients, while trying to achieve a dry-finished fermentation with as little left over YAN as possible for spoilage organisms to make use of.

I would recommend a rehydration-nutrient like Go-Ferm, regardless of wine type, style or nutrient supplied.

I would also recommend an organic form of nitrogen for the first of the staggered nutrient additions. This achieves several things; it provides an abundance of complex nutrients early in the fermentation to help open advanced metabolic pathways within the yeast, which keeps those early generations of yeast very content.

When DAP-based nutrients are added too early to a fermentation, they have adverse effects by encouraging the yeast to multiply at a pace so fast that they consume the limited micro- and macro-nutrients within the must, well before the wine is fermented dry. This leads to excessive creation of H2S (rotten egg smell) and potentially a stuck fermentation. It can also lead to over-toxicity from stressed yeast, which requires treating the wine with yeast hulls prior to pitching another yeast.

If DAP is a 'blessing' anywhere in winemaking, it's in the middle of the fermentation of Low-YAN musts. Low-YAN musts are things like mead, or wines with a low amount of fruit used / large amount of water used per gallon. Some grapes, some years, will naturally be Low-YAN as well. These fermentations are not possible to finish without issues, unless DAP is used (generally).

That's not to say you can't accomplish a Low-YAN ferment with Fermaid-O, its just cost-prohibitive.

Towards the end of a fermentation, when most are thinking of racking a wine to carboy - somewhere in that 1/2 to 2/3 sugar-break - winemakers like to add their last dosage of nutrients to ensure a dry fermentation. This is best done with organic nitrogen sources, as the yeast will soon stop the uptake of ammonia-based nutrients.

As a final note, the final tidbit that ties this all together. Yeast dont enjoy the switch between organic and inorganic nitrogen sources. While they will readily switch from organic to inorganic nitrogen, there is a lag phase when switching from inorganic (DAP, ammonia-based) nitrogen forms back to organic (amino-based) nutrient forms. They will stall, before picking back up. This stall is cause for worry amongst winemakers, because as I've noted, the proper time to use DAP is mid-fermentation, while the must sometimes calls for an additional dose of organic nitrogen prior to racking under airlock.

So this lag phase happens at roughly the same time the wine is racked, which leads to confusion as to why the wine stalled. Did I leave too much yeast behind? Did the yeast burn all the micro- and macro-nutrients? Is it a lag phase from switching from inorganic to organic nitrogen?

This will make a nice reference. Thanks!

Summarizes pretty good what we have been researching. Now if only the world would be ok with metric units....

BTW ppm=mg/L

I just prefer mg/L because it is more useful from a units perspective when it comes to using dimensional analysis.

I believe More Wine has two manuals, one for white and one for red, that details the same protocol. other good info in these manuals free for download.

Thanks for the info!

sal said:

I believe More Wine has two manuals, one for white and one for red, that details the same protocol. other good info in these manuals free for download.

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I have used those two manuals many times.

http://www.morewinemaking.com/public/pdf/wredw.pdf

http://www.morewinemaking.com/public/pdf/wwhiw.pdf

And their yeast guide:

http://www.morewinemaking.com/public/pdf/wyeastpair.pdf

For the sake of referencing: Most of the information in the initial post is the result of a collaboration that can be read in-depth here

Manley,
I have to admit, when you first posted this, it was beyond my comprehension, now that I have researched the heck out of nutrients, this is a real good reference that should be used.
You should write an article, I'm a firm believe that the more we understand about wine making, every step in the wine making process, the more proficient we can be, this will translate into making better wine with far less faults. I don't subscribe to the notion that we are home wine makers therefor we don't need to know certain aspects of the wine making process, or that home wine makers should be attempting various techniques and products.
Thanks again for your hard work!
(by the way...you are officially nominated as WMT nutrient guru...lol!)

Deezil said:

When DAP-based nutrients are added too early to a fermentation, they have adverse effects by encouraging the yeast to multiply at a pace so fast that they consume the limited micro- and macro-nutrients within the must, well before the wine is fermented dry. This leads to excessive creation of H2S (rotten egg smell) and potentially a stuck fermentation. It can also lead to over-toxicity from stressed yeast, which requires treating the wine with yeast hulls prior to pitching another yeast.

If DAP is a 'blessing' anywhere in winemaking, it's in the middle of the fermentation of Low-YAN musts.

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This is very interesting !

I had H2S problem by my previous batches .

By my first batch , I added DAP at the time of pitching and it led to H2S problem .

By another batch , I added DAP after formation of the Cap , as I had read it in an Article . But , it also led to H2S problem .

Now , you say in this Thread that it should be added in the mid-fermentation .

Do you mean that for example , in a Must which has 20 Brix , DAP should be added first at 10 Brix ?!

Is it possible to add Organic Nitrogen and vitamin B groups after formation of the Cap ?

Hector

DAP... Is a gift and a curse..

Fermenting with just-DAP, can work, but as you've noticed, it usually doesn't.

DAP is best-used in conjunction with another, more complete, yeast nutrient; this is how it fits into the middle of a Low-YAN fermentation. You'd use a 'complete' yeast nutrient (armed with micro and macro nutrients, as well as nitrogen) first - shortly after fermentation began; then use the DAP as a 2nd addition, half-way-ish through the fermentation, and finish up with an addition of organic-only nitrogen-based yeast nutrient (something like Fermaid-O)

I'm guessing that your H2S problem is coming from running out of the other nutrients needed, alongside the nitrogen, because it sounds like you may not be supplying them - and every ferment is different, with different levels of macro and micro nutrients, but most dont pack enough to finish a fermentation without assistance.

Your example is correct, but with that 1 addition of DAP @ 10 Brix, there'd also be an addition of something like Fermaid-O or Fermaid-K @ 18-19 Brix, and an addition of Fermaid-O between 5-8 Brix ... So while it wouldn't be the only addition of yeast nutrient, that is the proper timing


As for the organic part of your questions - that's usable at most-any stage of fermentation, as the yeast will consume that type of nutrient for a longer period than any other type of nutrient - in my writing above, it talks about the yeast stopping the assimilation/consumption of inorganic-nitrogen sources (DAP) after a certain extent during fermentation.. While they stop consuming inorganic nitrogen, they'll still consume organic nitrogen all the way to completion of the fermentation - you just want to make sure you dont end up with excessive leftover nitrogen for Other things (not yeast, but spoilage bacteria and organisms) to feed on.

Deezil said:

I'm guessing that your H2S problem is coming from running out of the other nutrients needed, alongside the nitrogen, because it sounds like you may not be supplying them .

Your example is correct, but with that 1 addition of DAP @ 10 Brix, there'd also be an addition of something like Fermaid-O or Fermaid-K @ 18-19 Brix, and an addition of Fermaid-O between 5-8 Brix ... So while it wouldn't be the only addition of yeast nutrient, that is the proper timing

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I always use DAP and "Brewers Yeast" tablets which is a natural source of B Group vitamins and contains a range of amino acids , minerals , trace elements and Yeast hulls . But , I always used them together after formation of the Cap .

I wish I had known the proper time for adding DAP !

Hector

I started to make a small red batch two days ago and this time I added 1/4 of a "Brewers Yeast" tablet after formation of the Cap and was waiting for 8-10 Brix drop in order to add DAP then , but on the 2nd day of fermentation , it started to emit H2S and Ethyl Acetate .

What is wrong this time ?!

Hector

yeast nutrient timing is very important as is the quality of the nutrient added. 100% DAP is like giving children soda pop and cotton candy , its garbage food for the yeast. a complete nutirent is always a better choice.

a proper rehydration regime is a good place to start . if you hydrate the yeast using goferm in the rehydration medium the yeast will get off to a good start and be protected from the shock of being pitched.

this goferm contains no nitrogen as high levels of nitrogen can actualy harm yeast in the very early stage of its life cycle . but its full of micronutrients that yeast needs to start its life out right.

so the goferm will protect the yeast from hydration untill the end of lag phase.
the lag phase is between pitching and the first sign of ferment , ie consistant bubbles in a white or the first little islands of grapes forming a cap.

it is at this time the yeast need their first addition of supplemental nutrient , fermaid K for example
fermaid K is a mix of inorganic nitrogen (DAP) organic nitrogen (yeast derived) vitamins , micronutirents , yeast hulls

the standard addition of fermaid K lallmand reccomends is 1 gram per gallon .

but they reccomend it is added split in two additions , the first one at the end of lag phase as described above , so you add 0.5 grams per gallon
at the end of lag phase (first signs of ferment)

and the second addition (0.5 grams per gallon) is at 1/3 of the way into the ferment . so in a must with a 25 brix starting point you add the second (final) addition at 18 brix . its ok if you miss it a bit , but be sure that you get it in the must before it is 50% dry .

never add nitrogen to a must after the 50% dry mark. the yeast cannot assimilate nitrogen at that late in its life cycle.

http://lallemandwine.us/products/nutrient_strains.php

http://www.lallemandwine.com/spip.php?rubrique4<=fr&td=1&univ=20


Fermaid O is an organic nutrient , it differs from fermaid K in that it doesn't contain thiamine or DAP .
It has a much lower nitrogen content and it may prove to not provide enough nitrogen for musts with very low natural YAN levels.
so you can use it and still get H2S or stuck fermentation risks.
So I would recommend it for religious organic winemakers who have the ability to test YAN.

anyone else who wants to use it should have some DAP on hand for intervention if h2s develops or use fermaid K for the second addition.

you time your fermaid O additions the same as the fermaid K protocol above .

DAP on its own added early in the ferment can actually cause a runaway ferment and unbalanced nutrition
causing rather than preventing H2S http://www.lallemandwine.com/IMG/pdf_WUP_3_-_2010_-_ORGNUT_-_US.pdf

so I reccomend a goferm and fermaid K combined nutrition protocol just like lallemand describes , especially for very ripe , under-ripe , hybrid or american native grape must all of which are known to be low in nitrogen and more prone to h2s. And it's important to remember it's not all about yan numbers , just because a must has the right numbers you can still have issues so using fermaid with naturally high yan is still a good idea , the other nutrients in it will help the yeast deliver the best flavours .

if yo know your grapes well and really want to help ward off h2s , using go ferm and fermaid K and optiwhite or optired are pretty bullet proof options. these extra SIY additions promote yeast health too.

also selecting a low h2s producing yeast and avoiding ones like montrachet is a good idea, as is racking off the gross lees 24-48 hours after pressing reds or the completion of white ferment.

Reviving a 7 month old thread

Can anyone help me understand the relationship between commercial products like Fermaid K and DAP with the yeast "nutrient" and "energizer" I bought at my LHBS?

Most yeast "nutrient" you buy at a store is DAP. Yeast energizer tends to be DAP plus vitamins.

Glad that stickman send me the link to this thread ...

Just got 2 pails from Brehm Vineyards of Syrah grapes but my YAN is 52mg/l

here is what was recommended :

Fermaid 6.5g - 6.5g - 3.0g
DAP 6.5g - 8.7g - 8.7g

Since my YAN is really low , should I break this in 6 additions instead of 3 ?

Thanks
T

I'm stuck at step one: Making an educated guess about the YAN content of my backyard red vinifera must, which can range anywhere from below 150ppm to above 500ppm.

JimInNJ said:

I'm stuck at step one: Making an educated guess about the YAN content of my backyard red vinifera must, which can range anywhere from below 150ppm to above 500ppm.

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When you don’t know the YAN, which is almost always for me, consider selecting a dosage right in the middle of the recommended range, administered in two doses, first as soon as fermentation gets going, second somewhere around 1/2 - 1/3 of sugar depletion. Then it’s a monitoring / paying close attention game, sniffing for the tell tale whiffs of H2S at every punch down. If you get a whiff while you’re above 1.020, a little shot of DAP and a couple of extra punch downs will knock it out, below 1.020, Fermaid O feels a little better for my risk tolerance to get to the end.

Other than Brehm frozen must pails, is there really any scenario where home winemakers actually know YAN levels?

Ajmassa5983 said:

Other than Brehm frozen must pails, is there really any scenario where home winemakers actually know YAN levels?

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That’s the only time I’ve known mine, but I’d suspect that there are vineyards that make wine as well as sell grapes, and may have that info available.