Home » Archive by category "Yeast"

Enhancing Yeast Starters

A great way to improve the overall quality of your beer and to ensure a great fermentation is to use a yeast starter.

This post builds on our previous posts, an introduction to Yeast Starters and 7 Questions and Answers About Yeast Starters.

If you would like to improve the process even further it is possible to enhance the yeast starter using one of a few different methods.

Swirling

As simple as it sounds, swirling a yeast starter every couple of hours will actually help you to grow more yeast. As the yeast starter sits still everything begins to settle to the bottom. When yeast piles up at the bottom of the flask it can not consume the sugars in the wort effectively, thus it can not multiply and strengthen. When you swirl the solution the yeast returns to suspension and can work more efficiently.

Constant Swirling

The only thing better than swirling your yeast starter regularly is swirling it constantly. This can be done with a stir plate. You can pick up a stir plate at just about any home brewing supply store. It is simply a platform that magnetically spins a little bar, which you place inside the flask with the yeast starter. As the bar spins it creates a vortex which constantly swirls the entire yeast starter. Stir plates can seem expensive for having a limited task, but the service they provide improves the output of your yeast greatly.

Aeration

A great way to help yeast proliferate is to add oxygen to the yeast starter. This can be done by shaking the flask fairly vigorously or even by setting up a diffusion stone to disperse oxygen into the beer. This setup can be tricky to pull off in a controlled yeast starter environment, and it brings other challenges. When oxygen is vigorously introduced into fermenting beer it produces diacetyl, which causes an off-flavor in the beer.

If you use this method of enhancing your yeast starter it will be necessary to refrigerate the starter for several hours to encourage the yeast to settle out. The liquid is then decanted off of the settled yeast, leaving only enough liquid to use in suspending the yeast so that it can be poured out. Since swirling the yeast starter using a stir plate introduces some oxygen to the wort anyway, you might find it easier to just use that method instead.

Temperature

This one is simple: no matter what type of yeast you are using, let the yeast starter incubate at temperatures of 75 to 80 degrees F to encourage yeast growth. Yes, this temperature works even if you are using a lager yeast that is generally kept at lower temperatures.

Yeast Nutrients

These days there is some debate about whether it is necessary to add yeast nutrients to a starter. Since liquid yeasts are produced to be quite robust and are packaged with nutrients already, it is possible that adding extra nutrients will not in fact be used by the already-satisfied yeast, but will instead be used by other organisms which will then grow and possibly cause off-flavors in the beer. Even so, many brewers still encourage the use of just a pinch of yeast nutrient for yeast starters. Often, the recommended quantity is just 1/8 of a teaspoon per pint of yeast starter. This enhances the viability of the yeast and speeds up fermentation.

Great Yeast Starter Information

An excellent video about yeast starters by Northern Brewer:

Have you tried any other methods of enhancing your yeast starters? What has worked well for you?

7 Questions and Answers About Yeast Starters

Taking your home brew to the next level requires some upgrades in your brewing process, and one of the most essential upgrades needs to be your yeast.

If you are brewing a strong beer, or would simply like to ensure that there is enough yeast to ferment your brew, the cheapest and most effective way to do so is with a yeast starter.

1. What is a Yeast Starter?

A yeast starter is a mini-batch of wort that is prepared to help yeast activate and multiply before being added to an actual batch of wort. A small batch of light dry malt extract is boiled and cooled, then a packet of yeast is added and allowed to grow for a day or so.

You can read an Introduction to Yeast Starters Here.

2. What Are the Benefits of a Yeast Starter?

There are at least five huge benefits to using a yeast starter:

1. A yeast starter will help yeast multiply so that there is a sufficient number of yeast cells to perform the fermentation, especially when brewing a stronger beer or a higher-volume batch.

2. Have you ever checked the manufacture date of your yeast? The older it is, the less viable the yeast cells are. If yeast is getting old and is less healthy (less viable) than usual, a yeast starter will bring it back up to strength.

3. Yeast will take action faster when added to the wort, limiting the chances for other microbes to take over and infect the beer.

4. While the same effect of raising yeast cell count can be achieved by buying two packages of yeast, the yeast starter will give the yeast a little bit of a kick-start and reduce the “shock” of being pitched into the environment of a strong batch of wort.

5. The boosted yeast cell count and the kick-started yeast will accelerate the fermentation process.

3.  When Should I Use a Yeast Starter?

There is rarely a time a yeast starter will not serve a brew well. A yeast starter is not always necessary when brewing lower-gravity (less alcoholic) beers, but it still brings benefits that will improve the beer.

In many cases a yeast starter is crucial. Brews with an expected original specific gravity of 1.060 or higher require a yeast starter to provide sufficient yeast for fermentation of such a strong brew.

Many brewers actually swear by yeast starters on any beer with a starting gravity as low as 1.040. Some home brewing stores say that all of their employees use a yeast starter for every single batch that they brew.

4. When Should I Not Use a Yeast Starter?

It is safe to pass on a yeast starter for an especially small batch of beer or one that has a low starting gravity. In these cases, adding too much yeast might cause the formation of some off-flavors.

When dry yeast is used for fermentation (as opposed to packets or vials of yeast in a solution) it is actually cheaper to just buy more packets of dry yeast than to buy the necessary ingredients for a yeast starter. Dry yeast does need to be activated in water before pitching it into the wort, but this is different than making a yeast starter for it.

5. What Volume Should My Yeast Starter Be?

The volume necessary for your yeast starter depends on multiple factors including the batch size and starting gravity of your beer and the age of the yeast you are using. In general the liquid yeast that you buy from the local home brewing supply store can be sufficient for a five gallon batch up to a starting gravity of 1.060 if the yeast is relatively young.

It is important to remember that the viability of the yeast (essentially, its health) decreases rapidly. If your yeast package was produced a month ago it is only 75-80% viable, meaning it has lost 20-25% of that original fermentation power.

There are formulas that will help determine the proper starter size after taking these factors into consideration, but we recommend using the handy MrMalty.com Calculator to make this process a lot easier.

Most home brewing supply stores sell yeast starter kits in both a One Liter size and a Two Liter size. Some supply shops even sell yeast starter kits in a Five Liter size. We have found a two liter yeast starter kit to work well for most everything that we brew.

6. What Specific Gravity is Ideal for a Yeast Starter?

Even if brewing a beer with a very high starting gravity a strong starter wort is not ideal. Create a starter wort with a gravity of between 1.030 and 1.040. Wyeast Labs, one of the two big producers of brewers yeast, recommends a gravity of 1.040 for yeast starters.

The idea is to create a starter that makes it easy for the yeast to activate and start multiplying. Creating a starter that is too strong might actually overwhelm the yeast and prevent it from becoming stronger.

7. How Do I Make a Yeast Starter?

If you are unsure about the details of making a yeast starter check out our post about that (with video) Here.

Want to learn how to enhance your yeast starter? Read more Here.

Want to learn more about yeast in general? Check out this book.