Yeast health is one of the most foundational factors when brewing exceptional beer. Today we’re looking at yeast nutrient, what it is, isn’t, and when/how to use it..
Yeast nutrient is typically a specific combination of ammonium phosphate, amino acids, vitamins, and minerals. It’s like a multivitamin for yeast. It makes sure they have exactly what they need to ferment your beer, cider, mead, or whatever.
Add yeast nutrient 10 minutes from the end of your boil. This helps it get mixed into your wort. Boiling for 10 minutes also ensures sanitation.
If using BSG Fermax, add a teaspoon to a 5-gallon batch. There are many producers of yeast nutrient. Each specific one will come with directions for use.
Without getting too nerdy, let’s look at what yeast nutrient brings to the table.
Yeast nutrient provides nitrogen (both organic and nonorganic) and phosphates, as well as minerals like zinc. Yeast need zinc to form alcohol. To put it too simply, yeast nutrient provides all the necessary components for yeast to live, ferment wort, and reproduce.
Nutrient gives yeast the things they need to build their cell walls, produce energy, etc. But an all-malt wort also contains all these things and thus nutrient isn’t always needed. With the exception of zinc.
It’s worth noting that zinc is the only mineral not included in an all-malt wort. If you’re not adding yeast nutrient (assuming it has zinc…because it does), then you should add zinc to every batch.
Having said that, there are plenty of people making good beer that don’t use yeast nutrient…ever.
When You Need It
You also want to use yeast nutrient when you’re brewing a high-adjunct beer. A beer brewed with rice, corn, or other sugar sources won’t have as much “naturally” occurring nutrients because you’re using less malt.
According to Dave Carpenter over at Craft Beer and Brewing, “In most standard gravity all-malt worts, you need not worry about yeast nutrient”. This is because malt contains everything yeast needs to be healthy and carry out fermentation. This fact is doubly true if you practice transferring a small amount of the trub from your boil kettle.
As I said before, if you’re not using nutrient then you really ought to be adding zinc. You can purchase zinc for brewing purposes and add it by itself.
I realized the other day that I’ve been using yeast energizer in place of nutrient for a couple years now. Guess I didn’t pay attention when I picked it up. I blame it on the fact that I was ordering everything in China using an online marketplace and struggling to read Mandarin Chinese. Oops.
Functionally, yeast energizer is used to get sluggish or stalled fermentations going again.
I’ll be…enter choice expletive…if I can get to the bottom of what the difference actually is. Some nutrients are said to contain diammonium phosphate. Northern Brewer says that yeast nutrients don’t have diammonium phosphate but only ammonium phosphate. But, like I just mentioned, that doesn’t seem to be true.
Another key distinction between energizer and nutrient is dead yeast cells. It’s a bit gross but yeast will consume the remains of their brethren in order to scavenge needed nutrients. A lot of sources seem to point to yeast energizer containing these “yeast ghosts” while nutrient does not. One notable exception of this is the White Labs yeast nutrient product called Servomyces. In Chris White’s book on yeast, “Yeast”, he mentions that Servomyces utilizes yeast ghosts.
The point is this. Use an energizer for getting a stuck fermentation going again and use yeast nutrient before fermentation starts. Because many of the nutrients on the market are proprietary formulas, we simply don’t know exactly what’s in them.
I trust that companies like White Labs and BSG etc know what they’re doing when they formulate yeast nutrient. Use as directed.
Yeast Nutrient and Beer Flavor
This is a broad overview and isn’t intended to be a deep look on the subject of yeast nutrient and beer flavor.
Adding yeast nutrient will change the flavor of your beer. At least it will affect how much fusel alcohols and esters are produced. Whether or not you’ll be able to taste a difference is another question.
Most of this is tied to the use of yeast nutrients including zinc. Dave Green over at BYO puts it this way, “…the addition of yeast nutrients with zinc will not only improve yeast performance, but the zinc has also shown to increase ester production”. That link for BYO is for a great article called “The Ester Family”. Read it!
Other Resources on Yeast Nutrition
For a more indepth look at some of the common constituents found in yeast nutrient, take a look at the article by Dave Carpenter.
And for a really detailed look at yeast and yeast nutrient, Check out the book Yeast by Chris White of White Labs.
Do you have to use yeast nutrient in every batch? No. But it’s a good idea and it’s cheap insurance.
Particularly if brewing high gravity beers, your yeast will thank you and your beer just might be a shade better too. It only takes a pinch.