If you have been homebrewing for many years like me, I’m sure you will have suffered the occasional slow or “stuck” fermentation, which can often result in undesirable flavors and aromas in your homebrew beer.
You may have followed the beer kit’s recipe to the letter and even used the freshest yeast possible but, for some reason, that healthy yeast doesn’t seem to want to do its job.
When it comes to brewing beer, yeast nutrient plays an important role in ensuring a healthy fermentation and a successful final product. Yeast nutrient is a blend of vitamins for cell growth, minerals, and other nutrients that help to promote a healthy yeast population during fermentation.
Yeast nutrients can be a controversial subject for many beer makers. While some swear by yeast nutrients for a more complete fermentation, old-school brewers argue that a good all-malt recipe shouldn’t need any extra nutrients for the yeast as natural nutrients will already be present in the grains. It’s split our local homebrew club down the middle on many an evening.
Personally, I think of adding a little yeast nutrient to my wort at the start of fermentation as a side insurance policy which ensures a healthier fermentation process. And you can’t add too much, can you?
However, the dosage of yeast nutrients needed per gallon of beer can vary depending on a number of factors. In this article, we will explore how much yeast nutrient you should use per gallon of beer wort when brewing.
Why Does Beer Yeast Need Nutrients?
Before looking at why yeast would need a nutrient or even what a yeast nutrient is, it’s important to understand the role yeast plays in the brewing of beer.
Yeast is a single-cell organism known as a eukaryote, meaning it has its own nucleus packed inside a nucleus envelope. Part of the fungus family, it is a living thing.
Yeast is literally everywhere and just loves sugars. The sugars which are found in wort for beer, from the breakdown of the starches in the grain, are highly attractive to the yeast and act as food or fuel for the yeast. As the yeast eats the plain sugars they convert sugars to alcohol and carbon dioxide, which turns the wort into a beer.
Unfortunately, yeast also needs other nutrients such as nitrogen, sulphur, and other essential vitamins and minerals for healthy growth and reproduction which can’t be found in simple sugars.
Although many of these nutrients can be found in the grains used, modern agricultural techniques and pesticides used can mean some of these natural nutrients can be missing. Without the proper nutrition, yeast may not be able to grow and function optimally resulting in a weak or hobbled fermentation process.
But it’s not just about the alcohol production and carbon dioxide that yeast produces. As the yeast feeds on those dead yeast husks, it also releases hundreds of secondary metabolites that can influence the additional flavors and aromas of the finished beverage.
Although yeast nutrients can be plentiful in wort, as beer is arguably one of the most nutritious alcoholic drinks due to the grains and hops being packed with nutrients, sometimes the wort can be lacking in nutrients essential for the yeast’s health and to get its job done.
The addition of yeast nutrients can be essential for producing your next beer batch and ensuring it has optimal flavors.
How Much Nutrient Does Your Beer Need?
The amount of yeast nutrient needed per gallon of beer can depend on several factors, including:
- Beer style: Different beer styles may require different levels of yeast nutrient to achieve the desired flavor and fermentation characteristics. Adjunct beers that have higher levels of fermentable sugars may be lacking in those other essential nutrients.
- Gravity of wort: The gravity of your wort (i.e. its specific gravity or density) can also affect poor yeast health and the amount of yeast nutrient needed. Higher gravity worts may require more yeast nutrient to support healthy fermentation.
- Yeast strain: Different strains of yeast may have different nutrient requirements, so it’s important to check the specifications of the yeast you’re using to determine the appropriate blends of yeast nutrients.
How Much Nutrient Should You Add? General Guidelines
As a general rule of thumb, you can use the following amounts of yeast nutrient per gallon of beer:
- For most ale styles, use 1/2 teaspoon of yeast nutrient per gallon of wort.
- For lager styles, use 1 teaspoon of yeast nutrient per gallon of wort.
- For high-gravity worts (1.060 or higher), use 1 teaspoon of yeast nutrient per gallon of wort.
It’s important to note that these are general guidelines, and you should always consult the specific instructions for the dosages of yeast nutrients you’re using. Some yeast nutrients may have different recommended amounts or instructions for use.
If you can’t find a commercial blend of yeast nutrient, you can always make your own yeast nutrient substitute using natural ingredients you can find in your home. (Link to best yeast nutrient substitutes post) Follow the same rule of a teaspoon per gallon recommended for most yeast nutrient blends.
When Should You Add Yeast Nutrient to Your Beer?
Yeast nutrient is typically added to the wort during the boil or fermentation stages of brewing. It’s important to follow the specific instructions for the yeast nutrient you’re using, as some may require a different method of addition or timing.
Here are the general steps for additions of yeast nutrients during fermentation:
- Sanitize any equipment that will come into contact with the yeast nutrient, such as a measuring spoon or stirrer.
- Dissolve the appropriate amount of yeast nutrient in a small amount of water or beer. This will help to ensure that the nutrient is evenly distributed throughout the beer.
- Add the dissolved yeast nutrient to the fermenter during the first few days of fermentation. This will help to ensure that the yeast has the nutrients it needs to thrive.
- Stir the beer gently to distribute the yeast nutrient throughout the beer.
Adding Yeast Nutrient to a Yeast Starter
If you regularly make and use yeast starters in your brewing, you may want to consider adding a yeast nutrient to the starter too. Ramping up those yeast cell numbers can be intensive for the yeast, which needs plenty of nutrition to create healthy new yeast cells.
Using a yeast nutrient rich in nitrogen, vitamins, zinc, and magnesium can be very beneficial. Obviously, you add less than when adding directly to the wort due to the smaller volume. Most yeast nutrient blends would recommend no more than 1/4 teaspoon to a 1500 ml starter.
If you store your yeast starter in the refrigerator for a couple of days before decanting it into your wort, you could also add yeast nutrient to the boil before pitching the yeast, but only use 1/2 teaspoon per gallon.
Whats the Difference Between Yeast Nutrient and Yeast Energizer?
It is important to remember yeast energizer and yeast nutrient are not the same thing.
Yeast energizers may be a type of nutrient blend but they will normally also consist of extra compounds too, such as Vitamin B, diammonium phosphate, tricalcium phosphate, magnesium sulphate, and yeast hulls or dead yeast cells.
Yeast energizers are used in the case of stuck fermentations to allow yeast cells and populations to increase in a batch of beer when they have been depleted due to an earlier yeast population growth. Whereas yeast nutrients are used at the beginning of fermentation to avoid those stuck fermentations happening by ensuring there are enough nutrients to support the early yeast cell count growth.
Can You Add Too Much Yeast Nutrient?
Yes, you can add too much yeast nutrient, but it is unlikely to happen unless you really go overboard. By following the manufacturer’s guidelines or sticking to the ‘a teaspoon to one teaspoon per gallon’ batch rule, most beer recipes shouldn’t be affected.
In extreme cases where you add too much yeast nutrient, your yeast may not be able to eliminate all of the nutrient additives, making for an off-tasting final product.
if you add too little yeast, unhealthy yeast can contribute those harsh alcohol flavors or a buttery flavor from too much diacetyl being produced, or an apple flavor from excess acetaldehyde. If the yeast doesn’t get enough nutrients it may not be able to finish the fermentation, especially when brewing higher-gravity beers.
The other risk is the production of ethyl carbamate, which can be dangerous to health if consumed in larger quantities. The FDA actually limits the amount of yeast nutrients that can be used in commercial wines because of this risk but has yet to make the same ruling for beers.
There is a slight danger of too much ethyl carbamate, a suspected human carcinogen, being produced as a result of too much yeast and yeast nutrient being consumed. But the amount of ethyl carbamate you would need to consume to pose a serious threat is much higher than that you may find in fermented food and drinks.
How Much Yeast Nutrient per Gallon? The Final Call
Do you need to use yeast nutrient in every batch of beer you brew? Probably not, some beers which use grains like malted barley will have more than enough nutrients in the grains without the need for added yeast nutrient.
However, when used in moderation, yeast nutrients are no bad thing. It can be reassuring when your airlock starts to bubble in just 6 – 8 hours and can ensure a healthy fermentation. Think of it as an insurance policy, and preventing a stuck fermentation is always better than trying to fix one.
Particularly when brewing higher gravity beers, the yeast will thank you and it’ll make for a better beer, too.
By following the recommended amounts of yeast nutrient per gallon of beer, and ensuring proper addition and distribution during fermentation, you can help to ensure that your beer turns out great every time.