How much yeast nutrient does starter wort need?

Question

I am going to make a batch of wort to be stored in 1 quart jars to make starters from. I'd like to add the yeast nutrient (diammonium phosphate and yeast hulls) at this time so I don't have to mix it when making the starter. How much (per gallon) should I use? The directions suggest adding 1/2 tsp per 5 gal of wort when making beer.

Since I don't know what I'll be brewing in advance, I'd like something that works for as many different types as possible. Is there a difference in the amount of nutrient needed for, an ale starter vs. a lager starter or a 1 stage vs. 2 stage starter?

Answer 1

For starter wort you can use the 1/2 tsp and a sachet of yeast hulls, although I usually double this, just to make sure the yeast have all they need. I've even used 1/2 tsp in a single 1 quart starter with no ill effects.

The yeast hulls are necessary since they contain trace elements that are essential for the yeast. The diammonium phosphate is only really needed if the wort is deficient in nitrogen or phosphates - not usually the case if making from extract or an AG brew, since the grain provides plenty. Still, it does no harm to add it.

You use the same wort/nutrients regardless of the yeast type - it's the size of the starter that counts, and by using a larger quantity of wort, you naturally have also more nutrients. Similarly, there's no need to differentiate wort from the first or second stage of a starter. When cultivating from 10ml slants, I use the same wort for all 3 stages.