Free tools for winemakers
Yeast nutrient (YAN) calculator
DAP or nutrient to reach a target YAN
DAP to add
Type the volume, the measured YAN, and a target or a sugar reading.
Gives a suggested target.
From the product's data sheet: how many mg/L of YAN 1 g/hL of it adds.
Above a legal DAP limit.
Split the addition.
DAP is limited by law. EU: up to 1 g/L of ammonium salts. US: up to 0.96 g/L (8 lb per 1,000 gal). A complex nutrient that contains DAP counts toward the limit too.
Work out the yeast and rehydration nutrient
How do we calculate this?
The exact formulas used in this tab:
What this calculator does
Works out how much DAP (diammonium phosphate) or complex yeast nutrient to add to bring a must’s yeast assimilable nitrogen (YAN) up to a target, and checks the DAP against the legal limits.
- Type the measured YAN, and either your own target or a sugar reading for a suggested one.
- To size the yeast itself, use the yeast pitch calculator.
The formula
Suggested target YAN by Brix (editable, UC Davis guide): 21 → 200, 23 → 250, 25 → 300, 27 → 350 mg N/L 25 mg N/L more per °Brix in between; 200 below 21, 350 above 27Rate (g/hL) = (target YAN − measured YAN) ÷ YAN per g/hLDAP: 1 g/hL adds 2.1 mg/L YAN (about 21% nitrogen, Enartis DAP data sheet)Complex nutrient: YAN per g/hL from its data sheetNutrient (g) = rate (g/hL) × volume L ÷ 100DAP limits: EU 1 g/L of ammonium salts (Reg. (EU) 2019/934); US 0.96 g/L (27 CFR 24.246)Split: half at the start, the rest about a third of the way through
Worked example
A suggested target
- 1,000 L of must
- Sugar: 23 °Brix
- Measured YAN: 100 mg/L
- Suggested target at 23 °Brix 23 °Brix → 250 mg/L
- How much is missing from the suggested target 250 mg/L − 100 mg/L = 150 mg/L
- DAP rate, at 2.1 mg/L of YAN for each 1 g/hL 150 ÷ 2.1 = 71.43 g/hL
- How much DAP 71.43 × 1,000 ÷ 100 = 714.3 g
Add 714.3 g of DAP: 357.1 g at the start and 357.1 g once about a third of the sugar has fermented
Past the legal limits
- Measured YAN: 50 mg/L
- Target: 300 mg/L
- How much is missing 300 − 50 = 250 mg/L
- DAP rate 250 ÷ 2.1 = 119.05 g/hL
- DAP per liter 119.05 ÷ 100 = 1.19 g/L
1.19 g/L of DAP, above both legal limits
Questions
Where does the suggested target come from?
From the UC Davis table that most yeast and nutrient makers print: 200 mg/L of YAN at 21 °Brix, 250 at 23, 300 at 25 and 350 mg/L at 27 °Brix. In between it adds 25 mg/L per °Brix, and it stays flat below 21 and above 27. Yeast strains differ a lot in how much nitrogen they need, so if your yeast supplier gives a figure for your strain, type it as the target.
How much nitrogen does DAP add?
DAP is about 21% nitrogen, so 10 g/hL adds about 21 mg/L of YAN. A complex nutrient adds far less per gram, and its figure varies by product. So the calculator asks how many mg/L of YAN 1 g/hL of it adds; that figure is on its data sheet. It can’t be more than 10 mg/L, because 1 g/hL is only 10 mg/L of product.
Enartis DAP data sheet.
How much DAP is allowed?
In the EU, up to 1 g/L of ammonium salts such as DAP. In the US, up to 0.96 g/L, which is 8 lb per 1,000 gal. A complex nutrient that contains DAP counts toward the limit too. The calculator warns when the DAP it works out passes either limit; make up the rest with an organic nutrient that has no DAP in it, or lower the target.
EU: Regulation (EU) 2019/934. US: 27 CFR 24.246.
Why split the addition?
Yeast takes up nitrogen best early on, and a large dose all at once can make fermentation run hot and fast. A common approach is half at the start of fermentation and the rest once about a third of the sugar has fermented. Avoid late additions: once alcohol builds up, yeast uses added nitrogen poorly, and what is left can feed spoilage microbes.