Dry Hopping and input of nitrate to the beer

As dry hopping shows increasing importance, we are extensively investigating its influence on aroma and bitterness. At the same time we have to be aware of hops as a nitrate storing plant. In the cone concentrations of nitrate can be found up to more than 1000 mg per 100 g of hops.

Therefore we examined several beers from our test program for nitrate. The results we found were within a range of 23 to 40 mg nitrate per liter. These concentrations are still below the drinking water regulations of the US, which is 45 mg/l and Europe, which is 50 mg/l. Although these results are still satisfying, care has to be taken, as some beers were rather close to the maximum residue level for drinking water. The nitrate level in the initial beer and in the hops used for dry hopping, as well as the dosing rate have a strong influence on the final concentration in beer.

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