Nitrogen

Nutrients

Vitamins

Grapes attacked by mold or noble rot can present a lack of B1 vitamins. In this case, winemakers add around 50 mg/hL of thiamine combined with other nutrients to help fermentation.

How to use it ?

Depending on the fermentation stage, it may be interesting to use inorganic or organic nitrogen. It is usually recommended to use the inorganic form at the beginning of the fermentation and the organic form during the fermentation. This way, it helps to quickly start the process and prevent the production of H₂S during it.

Timing

The best way to determine when to add nutrients is required, depends on the existing native YAN concentration in the musts and the gap between the deficiency threshold and the recommended YAN concentration.

In order to homogenize nutrients in the must, they are usually added by pumping over with oxygen (reds) or mixing with inert gas (whites/rose).

Nutrient	Recommended dose	YAN percentage for 1 g
Diammonium phosphate (DAP)	20 - 40 g/hL	21 %
Ammonium sulfate	20 - 40 g/hL	21 %
Inactivated yeasts	20 - 40 g/hL	Various products
Autolysed yeasts	20 - 80 g/hL	Various products
Yeast hulls	10 - 30 g/hL	//////
Thiamine	50 mg/hL	//////

Practical application

Deficiency

The Deficiency threshold is around 150 mgYAN/L for wines with 12% v/v alcohol potential.

Deficient musts always produce rotten egg smell due to the H₂S productionH₂S or dihydrogen sulfur is synthesis by yeasts in musts with nutrients deficiency. Without nitrogen's ressources, yeasts start using sulfur amino acids (cysteine and methionine) which release sulfur in musts. This sulfur combines with hydrogene and produces hydrogene sulfur (rotten egg smell)..

Lack of nitrogen decreases esters synthesis.

Excess

An excess will surely improve fermentation kinetic and yeast population growth but it will also increase temperature and nutrient competition which will raise the yeasts death rate and may cause H₂S production, sluggish or stuck fermentations.

The right dose

The next tables will help estimate all the parameters needed :

The Recommended YAN and deficiency threshold concentrations.

The Nutrients quantities required for one or two specific products.

The right moment to add your product.

All those parameters are measurable using your own must properties.

This website is not absolutely affiliated to any laboratories or nutrient producers. A list of different products is provided based on their popularity but if your favorite brand is not available, please contact us and we shall update the list.

Step 1 : Estimate the YAN concentration

The next table will give you the required YAN oncentration and the deficiency threshold using different methods.

Click below depending on the unit you are used to working with.

Step 1 : Estimate required YAN concentration

Masse volumique corrigée (kg/m³)	Brix corrigé (°Bx)

Sugars (g/L)	ABV (% v/v)

If you are not satisfied with the required YAN result, you can change it as the program will use the new value.

Required YAN (mgYAN/L)	Deficiency threshold (mgNass/L)

Step 2 : Must and nutrient properties

Now, we have to focus on nutrient and must properties in order to measure the required doses. The next table shows how to use one or two nutrients (mixed combination). Later you will be able to choose which percentage of each you want to add (step 3).

Use the lists below to choose your product(s). In case you are using only one product, just fill one column.

Step 2 : Must and nutrient properties

Must/juice volume (hL)	YAN native concentration (mgNass/L)

[Nutrient 1]	[Nutrient 2]

Step 3 : Nutrient distribution percentage

It's time to choose the distribution percentage for each product you have previously chosen (step 2).

If you have decided to use only one product, fill the same column (color) and enter 100%.

Step 3 : Nutrient distribution percentage

Remaining YAN concentration to add (mgNass/L)

Desired proportions

Once this table is completed, the last step will give you all the concentrations, quantities and optimal addition time.

Step 4 : concentrations and quantities needed.

Concentrations needed

Quantities required

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Optimal time

Formaldehyde titration

kesako?

Formaldehyde titration is a technic to evaluate nitrogen concentration in musts/juices.

The formaldehyde solution will react with the nitrogen in the juice and release protons which will lower the pH solution. Then using caustic soda / sodium hydroxide we can measure the YAN concentration (inorganic and organic forms).

Tools and reageants

Sodium hydroxide (NaOH) / caustic soda 0.05M (mol/L).

Formaldehyde 37%.

pH meter.

Graduated burette + support

Beaker.

Pipettes.

Paper filter.

Make titration beforehand

Make distilled water, here are 3 different ways to do it.

Before titration, make sure the formaldehyde solution is pH8 using the pH meter. If not, add 10% caustic soda until pH reaches 8.

Protocol

Using the beaker, filter 10 mL of must (filter paper) then add 25 mL of water and mix.

Put the pH meter into the beaker and stir.

If more than 150mg/L dioxyde sulfur has been added to the wine, add 1mL of 3% peroxyde hydrogene solution and stir.

Check the pH solution and balance to pH8 using the caustic soda 0.05M.

Add 2 mL formaldehyde and stir.

Start the titration, add caustic soda until you reach pH8 and measure the quantity using the burette (mL). Enter the value in the table below.

YAN concentration

NaOH concentration (mol/L)	Volume sample (mL)	Volume distilled water (mL)	NaOH added (mL)

YAN concentration (mg/L)

Conclusion

This method is extremely simple for measuring inorganic and organic YAN but Formaldehyde will react with all amino acids. However, during fermentation process yeasts will have difficulty metabolizing proline, one of the most abundant amino acids. That is why you must lower a little bit the obtained YAN concentration value.

Furthermore, formaldehyde is a dangerous chemical, don't touch it or smell it. You should always work in a ventilated area and wear gloves, glasses, lab coat and mask.

Download the product toxicity report

Sources

BELL, S-J. & HENSCHKE, P.A., 2005. Implications of Nitrogen Nutrition for Grapes, Fermentation and Wine. Australian Journal of Grape and Wine Research, 2005, vol 11, issue 3, 242-295 pp.

BELY, M et al., 1994. Assimilable Nitrogen Addition and Hexose Transport System Acitivity during Enological Fermentation. J. Inst. Brew, 1994, vol 100, 279-282 pp.

Bisson, L.F., 2014. The Role of Nitrogen in Yeast Metabolism and Aroma Production. Department of Viticulture and Enology, UC Davis.

BLATEYRON, L. & SABLAYROLLES, J.M., 2000. Stuck and Slow Fermetations in Enology: Statistical Study of Causes and Effectiveness of Combined Additions of Oxygen and Diammonium Phosphate. Journal of Bioscience and Bioengineering, 2001, vol 91, no 2, 184-189 pp.

Methods in Biotechnology, Vol. 14: Food Microbiology Protocols.

CABOULET, D. et al (IFV). Nutrition azotée et levure : un levier pour piloter le profil aromatique des vins. Institut Français e la Vigne et du Vin [en ligne] (2014). Disponible sur : http://goo.gl/a99tlT

Gump, B.H. et al., 2001. Prediction of prefermentation nutritional status of grape juice. Methods in Biotechnology, Vol. 14: Food Microbiology Protocols.

MANGINOT, C. et al., 1998. Nitrogen demand of different yeast strains during alcoholic fermentation. Importance of the stationary phase. Enzyme and Microbial Technology, 1998, vol 23, 511-517 pp.

ORGANISATION INTERNATIONALE DE LA VIGNE ET DU VIN. Codex oenologique international : Produits utilisés en œnologie, Phosphate d'Ammonium [en ligne]. Brochures techniques, 2013. Disponible sur : http://goo.gl/D4ICUF

SABLAYROLLES, J.M. & SALMON, J.M. Vitamins : importance in alcoholic fermentation. In Lallemand Research Meeting, April 27-30 2001, Perugia, Italie.

Products	YAN per 1g (%)	Type
Fermaid AT	12 %	organic + inorganic + thiamine
Fermaid E	14 %	organic + inorganic + thiamine
Fermaid E blanc	16 %	organic + inorganic
Fermaid K	13 %	organic + inorganic + thiamine
Fermaid O	4 %	organic
Nutristart	14 %	organic + inorganic + thiamine
Nutristart Org	7 %	organic
Diammonium phosphate (DAP)	21 %	inorganic
Ammonium sulfate	21 %	inorganic
Thiazote /SP/PH	21 %	inorganic + thiamine