We’ve all read and heard about the importance of yeast nutrient in our beer, mead, and wine, but it’s something many homebrewers consider an afterthought. I know that, in the past, I typically didn’t use it at all for beer, and only occasionally used it for especially big meads or stuck fermentations.

So that brings up the question: is yeast nutrient necessary? What exactly is the purpose of it? And which of the many yeast nutrient products on the market are worth considering?

This article isn’t going to provide you specifics into which products to actually use. The answer to that question varies so widely from batch to batch depending on what you’re actually brewing.

For that reason, there will be other articles in the future (which I will list here for your convenience) detailing the nutrient needs of different brews, from beer to mead to wine.

(I actually wasn’t going to even write this article originally. I was planning to jump right in with the articles specifically about using yeast nutrient in beer, mead, wine, etc; but the more I did my research, the more I quickly realized that it would be useful to document the actual nutrient needs of brewer’s yeast at a high level, to reference back to in the other articles in the series.)

Why Should You Use Yeast Nutrient?

Is using yeast nutrient even necessary?

Well, the answer is typically… no, it’s not strictly necessary. Under the majority of circumstances, your yeast will eat the sugar you provide it and produce alcohol even if they are malnourished and starved of the various vitamins and minerals that they need to be healthy.

However, that question is comparable to asking, “Is it necessary for me to eat a healthy, balanced diet?”

If you look at the nutrient needs below, you might notice that a lot of the vitamins and minerals that yeast needs are the same ones that humans do – and they perform similar functions in our systems as well.

Many people around the world have wildly unhealthy diets, and are deficient in all kinds of macro- and micro-nutrients, and they still live – but poor diet also typically leads to all kinds of health complications, and often, reduces a person’s quality of life.

So it goes for yeast, as well. And when our yeast has poor health, or is especially stressed out, this can lead to all sorts of fermentation problems: poor attenuation, stuck or stalled fermentations, off-flavors, etc.

Thus, while yeast nutrient is not strictly necessary to get your yeast to produce alcohol, it is important in order to actually produce a quality product in the end.

Different ingredients and sources of fermentables provide different amounts of the various nutrients that yeast need, which means that different brews will have different nutrient requirements. Standard-gravity beers usually have most of the nutrients that yeast need already in the wort, while a traditional mead or seltzer is basically a blank slate, with no nutrients provided to the yeast other than sugar.

It’s important to understand what your yeast need, and what is provided by the ingredients you are using, in order to figure out how to supplement the wort or must with nutrients to ensure your yeast are able to ferment along happily and healthily.

Figuring out nutrient additions are another (very important) part of recipe building!

What (Specific) Nutrients Does Brewer’s Yeast Need?

In addition to the sugar your yeast are fermenting (the only absolutely necessary ingredient to actually make alcohol), brewer’s yeast also utilizes a number of other nutrients in order to have a healthier, more effective fermentation.

These nutrients can be split into 3 categories: nitrogen, minerals, and vitamins.

Nitrogen

Nitrogen is an essential component in yeast metabolism. It is the most important yeast nutrient, and the one that most products on the market focus on.

I won’t get too deep into the actual microbiology of what yeast cells use nitrogen for, but in summary, it is used for protein synthesis, the actual process of taking in sugar molecules for consumption, and in parts of the metabolism process during which the yeast cells produce aromatic and flavor compounds such as esters.

Without enough nitrogen, the fermentation will proceed slowly or stop altogether. Worts and musts deficient in nitrogen may also produce brews lacking certain flavor compounds, or result in stressed fermentations producing off-flavors.

There are two sources of nitrogen important for consideration in homebrewing: Free Amino Nitrogen (FAN) and Yeast Assimilable Nitrogen (YAN).

Free Amino Nitrogen (FAN) simply means any free-floating amino acids (containing nitrogen) that are readily and easily taken up by yeast cells. FAN is usually more associated with beer, since standard wort (from malted grain) has an abundance of FAN, making it a fantastic source of nitrogen for your yeast.

Yeast Assimilable Nitrogen (YAN) can often include FAN, but when the term “YAN” is used, it typically indicates other sources of nitrogen, as well. YAN refers to any source of nitrogen that yeast are able to use (whether easily or not). YAN often includes ammonia or ammonium.

The term “YAN” is typically used more in the wine and mead world. Fruits (including wine grapes) can often provide varying amounts of YAN to the must. Additionally, most yeast nutrient products that contain nitrogen provide it via YAN rather than just FAN.

Minerals

When referencing yeast nutrient, brewers typically think primarily of the nitrogen requirements of yeast. However, there are quite a few other minerals that are important, as well, and often get overlooked.

Minerals give the yeast cations and anions. Don’t worry too much about the specific chemistry – it’s important to just realize that these minerals are useful in various cellular processes, and in aggregate, are essential for yeast cell growth, reproduction, and metabolism (fermentation).

Minerals are typically present in varying amounts in your wort or must (unless you are using only honey or plain sugar as fermentables, in which case there may not be any minerals). Depending on the hardness of your water, most of the minerals may also be provided by your water.

If you are using RO water, or distilled/spring water purchased from the store, your water may not actually have any minerals in it – in this case you will need to consider the mineral needs of your yeast when building your water profile.

The table below provides a list of the specific minerals that yeast need, as well as some notes on the purpose of these minerals in your yeast’s cellular processes.

Mineral	Notes
Phosphorous	Yeast needs a lot of phosphorous; DAP does provide plenty. It’s a key component in ATP (cell energy) It’s a key component in DNA and other structural molecules for cells It’s usually plentiful in wort & fruit
Sulfur	Sulfur plays a critical part in yeast metabolism & fermentation
Chloride
Potassium	Plays an essential role in many cellular processes
Sodium
Magnesium	Helps with yeast growth & fermentation More magnesium usually results in more esters and less fusels
Manganese	Helps with yeast growth & fermentation Wort is not deficient in manganese usually, as it’s provided by the hops
Calcium	Can act as a pH buffer, resulting in less-stressed and longer-living yeast cells, even as pH in the environment might vary outside the yeast’s preferred range Helps with yeast flocculation Calcium should be balanced with Magnesium in a roughly 4:1 ratio; above that, the calcium will prompt the cells to stop uptaking Mg, resulting in a fermentation starved of Mg even if it is present
Zinc	Critical for fermentation performance, particularly in the later stages Necessary for conversion of acetaldehyde to ethanol; zinc deficiency results in off-flavors as a result Helps with flocculation Wort doesn’t typically provide much zinc, and water sources tend to be very low in zinc in most places. Wort often needs to be supplemented with zinc more than anything else
Copper	Essential component of some enzymes Only a tiny amount is needed
Iron	An essential cofactor for enzymes in numerous cellular processes

Vitamins

In addition to the mineral needs, yeast cells also require B vitamins in their diet, just as we do as humans.

B vitamins are used throughout the metabolic cycle, and help yeast break down the sugars they are eating in various ways.

If your yeast have enough B vitamins available, it will speed up the fermentation process, result in better attenuation, and help the yeast to be less stressed, so they produce fewer off-flavors.

There are several B vitamins important to yeast, but it’s not actually important which specific B vitamins there are. What is important to understand is that dead yeast cells are the perfect source of every vitamin that healthy yeast need to do their job. Yeast are cannibals, and will consume other dead yeast cells for nutrition!

Adding yeast nutrient at the beginning of fermentation is important, because it helps the fermentation process get going quickly and healthily at the start. However, as fermentation goes along, your active yeast population will turn over a few times, and the early generations of yeast cells will die – providing a continuing source of vitamins for future generations!

Malted grain (in most standard worts) is also a great source of B vitamins, and probably will not need extra supplementation.

What Are the Best Yeast Nutrient Products?

Now that you know what your yeast need, how do you actually achieve it? What can you do to ensure your yeast have all of the vitamins and minerals they need to grow up happy?

There are a ton of products on the market, but I will go over the most commonly-used options here.

The purpose of this article is not to tell you what the best option is, just to provide a reference so you know what you’re actually working with. Every batch of homebrew has different requirements, based on what you’re actually brewing, the yeast strain’s individual requirements, and what the ingredients you’re using already provide.

There’s no single “magic silver bullet” – or rather, a single product that is optimal for every single situation. It would be impossible to detail every single option for every single situation in this article. Future articles will go over what’s best depending on what you’re making (beer, wine, mead, etc.), and this article serves as a reference point to detail both what you’re trying to accomplish and what options you have.

However, anything is better than nothing, and if you want to just buy one thing and use it for every batch you make, that is an option – albeit maybe not the best option.

If you want to forego reading about the best options and just want a one-size-fits-all solution, then my personal suggestion is to get either Wyeast Yeast Nutrient or Fermaid O in bulk and use that according to the label’s specifications.

But if you want to know more, I will detail below the popular yeast nutrient options.

Boil Your Own Yeast Nutrient

The primary source of vitamins and minerals in most yeast nutrient products on the market starts with dead, autolyzed yeast cells. Dead yeast can provide all of the B vitamins that healthy yeast need, along with any nitrogen and other minerals that were present in the yeast cell before it died.

So doesn’t it make sense, if you have access to yeast, that you could make your own simply by killing the yeast and providing the dead cells to your fermentation?

This is a common solution that the especially cost-sensitive brewer uses when he or she doesn’t have access to (or can’t afford) the other solutions. It’s a great way to approximate other solutions such as Fermaid products or Servomyces.

To do this, you can simply take another source of yeast (such as a packet of dry yeast you have laying around, scooping out some of a yeast cake from a previous batch, or even just getting some cheap bread yeast at the grocery store) and boil it for a few minutes. Boiling it ensures that all of the microbes, including the yeast cells, are killed. Then just add it to your batch as you pitch your preferred yeast for fermentation!

There’s a reason it’s not the best solution, however. While it does a good job of approximating what some of the other products are doing, and can be a source of some nutrition for your yeast, it’s not perfect.

Other products that use autolyzed yeast cells first pump them full of all of the nitrogen and other nutrients that healthy yeast will need before killing them – ensuring that the dead yeast cells have everything a growing yeast culture needs.

You can’t be sure that your previous batch of yeast – or especially that packet of bread yeast – has the full range of nutrition before they’re killed. That wasn’t their purpose when the yeast was cultured – whereas it is the purpose and goal when culturing up yeast for the manufacture of something like Fermaid O or Servomyces.

I guess you could take one of these sources of yeast, culture it up yourself and pump it full of nutrition, before boiling it… but yeast nutrient is pretty cheap, and that sounds like a lot of extra steps, so why not just purchase a product that’s already had that done professionally?

Diammonium Phosphate (DAP)

Diammonium Phosphate (usually referred to as simply “DAP”) is just what it sounds like: two ammonium molecules bound to one phosphate molecule.

It’s an easy source of two nutrients that are the most beneficial to proper fermentation: ammonium is a good source of YAN, and phosphorous is also an important nutrient. Both are imperative to fermentation, yet most meads, country wines, and other sugar-based brews have little to none of them available to the yeast.

On its own, DAP is not a great option. It’s often described as similar to giving your children candy (rather than real food). It gives them a quick sugar rush, but then they crash and get cranky; plus it’s not particularly healthy.

DAP is a source of nitrogen, but lacks most of the other nutrients that healthy yeast need. It can give your yeast a big boost at the start of fermentation, but they will chew through it quickly, and then will be forced to continue fermentation without proper nutrition.

In addition, yeast cannot uptake DAP after the alcohol concentration of their environment gets above about 9%, meaning it becomes useless later on in fermenting bigger brews (which are usually the batches that need nutrient additions the most!)

DAP is a cheap source of yeast nutrient. If you use DAP, it’s usually best to do so in combination with other products. Many products include DAP as one of the ingredients.

Fermaid (O + K)

There are two Fermaid products on the market: Fermaid K and Fermaid O.

Fermaid K came first. It was produced primarily from autolyzed yeast and DAP. The autolyzed yeast are intended to supplement DAP with not only extra nitrogen (in the form of YAN) but also many other vitamins and minerals that healthy yeast need. It’s described as a blend of both organic and inorganic nutrient sources.

Fermaid O was developed much later, and was intended to be an improved version of Fermaid K. It’s also produced primarily from autolyzed yeast, but it does not include DAP. As such, it’s supposed to provide a healthier, steadier source of nutrient compared to Fermaid K – and is considered by many homebrewers to actually achieve this goal, making it the preferred option between the two. It’s described as a completely organic source of yeast nutrient.

Fermaid products were designed with mead and country wines in mind. As such, the focus of the product (and the marketing) is the abundance of nitrogen it provides. It does also provide other vitamins and minerals.

Servomyces

Servomyces has been around for a relatively long time, and was at one point the preferred source of yeast nutrient for beer (and other primarily grain-based brews).

Servomyces is dead, autolyzed yeast cells – nothing more, nothing less. The yeast grown to be used in Servomyces are specifically cultured to have everything that the next generation of healthy, active yeast will need for a good fermentation. It’s also made with beer in mind, rather than wine or mead (which seems to be a bit of an uncommon thing in the industry). This means that it’s supposed to be higher in things like zinc and magnesium, which wort is typically missing.

Other products have since come along and displaced Servomyces as the preferred source of yeast nutrient, primarily because Servomyces is more expensive than a lot of the other options.

However, Servomyces does still serve a very specific purpose: it was developed to be a fantastic source of yeast nutrient, designed with beer in mind, that follows the German Reinheitsgebot (RHG) laws.

(I’m sure you’ve heard of the law, even if you haven’t heard the term; according to the law, beer is meant to only include “Malt, Hops, Water, Yeast” and nothing else.)

Since Servomyces is only dead autolyzed yeast cells, it counts as just adding yeast to your brew!

Brand Name Nutrients (Wyeast, White Labs, others)

There are a number of yeast nutrient products developed and sold by the companies that we, as homebrewers, typically get our yeast from, such as Wyeast and White Labs. The nutrients are meant to go hand-in-hand with their yeast.

Click here to purchase Wyeast yeast nutrient on MoreBeer.com, or alternatively, click here if you prefer the White Labs yeast nutrient product.

These products are typically not based on dead yeast cells, and are instead a concoction of the nitrogen and various vitamins and minerals that are necessary for yeast health, freely combined, usually in powder form.

The exact mixture of each is not published by each manufacturer. It’s probably safe to assume that any of these products are basically the same as any other, though the exact mixture probably differs a little bit.

Wyeast yeast nutrient appears to be the most popular of these options, especially amongst beer-brewers, where it has displaced Servomyces as the preferred option. This is mostly due to price – Wyeast appears to accomplish the same thing as both Servomyces and other brand-name nutrients (such as White Labs) but at a lower price-point.

However, it does not conform to German RHG laws, so if you’re concerned about that, you’ll need to look at other options.

Why Urea is BAD For Your Beer, Mead, or Wine

The final product of note is Urea, which homebrewers have used and recommended as a cheap option in the past.

Important note: Urea is NOT urine! You’re not adding pee to your homebrew.

However, more recently, it’s been discovered that urea is actually BAD for you!

Urea conversion in the presence of alcohol can produce ethyl carbamate, a carcinogen.

It is up to you, as a homebrewer, whether this bothers you or not. Urea is still freely available on the market. The cancerous effects of using urea may not be huge (everything gives you cancer these days, after all) and alcohol is, itself, a carcinogen, so you’re already indulging anyways.

However, urea isn’t that great of a source of yeast nutrient anyways, so, given that it’s also not good for you, there’s no real reason to choose it over any of the other options presented in this article.

I suggest not using urea, and it’s always recommended not to by other homebrewers when the discussion comes up.

Conclusion

The purpose of this article is not to prove anything, offer advice, or describe how to do anything.

It’s meant as a backdrop of information – a reference point, so you have the knowledge to understand your yeast better and what options are available to you for providing your yeast with the nutrition they need.

In future articles, we’ll discuss the actual best options, as well as how to properly add nutrients for best results.