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Calculating Nitrogen requirements for Bourbon Mashes


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Hello folks,

I've been trying to nail down my whiskey ferment performance and was wondering if anyone had any good resources for calculating nitrogen needs for grain washes.

I haven't looked terribly hard, but I haven't seen any kind of information for determining YAN from total percentage Nitrogen in a particular grain. I realize there's probably not a simple answer, but any help getting me pointed in the right direction would be appreciated.

I just read an abstract that stated that a particular variety of corn contained 1.5 ish % nitrogen, so if 100% of that nitrogen was extracted into the wort and was yeast-available, that would come to 2270 ppm (if I plug in my mashing numbers... this is just for the 51% rolled corn and doesn't count the other 49% of malted barley), which is WAY above what is recommended from most guides online for nitrogen additions (granted, they are mostly concerning wine fermentation). I'm guessing that only a very small fraction of the total nitrogen in the grain can be extracted into the wort as YAN.

We also separate the grain solids with rice hulls, so I imagine that some of the nitrogen in the grains doesn't have time to become extracted into the wort (compared to a non-filtered mash).

Since I'm almost certain that my last fermentation was nitrogen deficient (slight H2S smell, sluggish), I'd like to have another nitrogen dosage plan separate from the ones that are floating around for wine. I plan on using Fermaid K and Dap for now, but any other N sources that anyone could recommend for grain would be appreciated.

I'll be happy to share any sheets I make when I can nail down a halfway decent formula.


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My limited understanding is YAN will vary depending on the particular lot of grain, but I would imagine it would remain inside a reasonable range for each mashbill. At our winery we test YAN for wine with a UV Spec, and we plan on using it for whiskey mashes as well when the time comes. I would imagine you could always send out a sample for testing for relatively cheap to a lab or maybe even a nearby winery or brewery. That wouldn't tell you what you need specifically for each batch, but it can give you a pretty good ball park.

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I am just digging into Whiskey mashes myself and this maybe a stupid question but, would it hurt or be beneficial just to add diammonium phosphate anyways? I have added it to my wine fermentation for years but have never heard if people do to a whiskey fermentation.

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Excessive DAP can cause later deficiencies because it encourages a large biomass buildup. The biomass cleans out all available nutrients before fermentation is complete. DAP itself can lead to H2S formation in certain conditions.

Malts typically have plenty of yeast assimilable nitrogen. No point in wasting money in DAP IMO.

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