Flavor effects of adding yeast energizer or nutrient to beer?

Question

My understanding is that generally (with the possible exception of starters) yeast nutrient and energizer are not really needed for beer, as the barley provides basically everything required.

However, is there any possible downside to adding them? Obviously using it when it adds no value is wasteful but is there anything in yeast nutrient or yeast energizer that would adversely affect the beer if too much is present in the final product?

On the other end, the yeast energizer I have lists its ingredients as diammonium phosphate, Springcell, and magnesium sulfate. Of these, magnesium sulfate sticks out as something that might benefit hoppier beers. I would imagine the amount in the yeast energizer would be relatively small, but maybe they could be high enough to make a noticeable difference?

More generally, are there any possible flavor impacts of yeast nutrient or yeast energizer if added to an otherwise normal batch of beer? I'm mostly thinking all-malt beer, but if this might be different for wheat beer or similar then I would be interested in that as well.

Answer 1

I've seen in the literature that yeast nutrient based on aminoacids can contribute soy/umami or slightly metallic flavor -- obviously, for that it needs to be incompletely consumed by yeast. For that matter, I'd be careful about adding too much nutrient.

On the "absence of positive impact" I beg to disagree. I made a habit of adding some nutrient to my starters and, for heavy beers, to the kettle at flameout. The theory (I am sure I picked it from Palmer's podcast) is that while the wort still has oxygen, yeast grows, and, while growing, consumes nutrients.

Answer 2

I would say it would not really affect your beer, depending on how much you put.

First thing is that, the important thing when pitching your wort is the pitch rate, which is the concentration of yeast in the wort per degree plato. Adding nutrient will not benefit this, because you will still have to wait until the yeast grows if you pitch too low.

I would use those nutrients in a starter before pitching to get the right amount of yeast cells that your wort requires to start a healthy fermentation.

About any downsides to adding, let's say your pitch rate is good, then adding nutrients to your beer will just add work for your yeast, not really benefiting your beer.

However, I don't know about the taste of those or impact to taste of them.