While dogs are widely known as man’s best friend, brewer’s yeast should be just as widely known as the brewer’s best friend. What appears to be nothing more then a mere single-celled organism is in fact alive and fully capable of magic that’d make David Copperfield’s jaw drop. While pulling a rabbit out of a hat may impress the kiddos, yeast can perform a feat that serves a bigger purpose; turning sugar water into delicious beer through the wondrous process of fermentation!
Maintaining Yeast Health
While yeast is capable of such an impressive act, like any performer it puts on the best show when it’s healthy. Regardless of whether you’re using dry or liquid yeast, it’s important to ensure that your yeast is in its best possible condition to properly convert the sugars into alcohol during fermentation.
With dry yeast, this means keeping it in a cool, dark place. While it isn’t imperative that it be refrigerated, it never hurts.
Dry yeast has a shelf life of about a year, and every packet should have a package date for reference. This dried form is great for novice to intermediate homebrewers because it comes in higher cell counts that are conducive to productive fermentation without much additional effort.
However, it can be helpful to rehydrate the yeast prior to pitching by adding yeast to a cup of 100°F water and then adding a small amount of malt extract or sugar dissolved into water. After a half hour the yeast mixture should be foaming letting you know that the yeast is alive and well, and ready for pitching.
Liquid yeast can be a bit trickier because of its higher level of perishability. It should also be stored in a dark place but unlike dry yeast it is important that the storage temperature remain low. A refrigerator makes a great home for liquid yeast until brew day.
Depending on the type of container, liquid yeast typically has a shelf life of about 4-6 months. Each type has its advantages but liquid is the form that offers more possibilities, not only in the amount of styles you can make with it, but also in its overall viability and effectiveness potential. However, liquid yeast also comes in lower cell counts so depending on the strain and recipe it may need to be cultured prior to pitching by use of a yeast starter.
One of the first upgrades homebrewers choose to make as they progress and begin to gain a better understanding of the brewing process is a yeast starter kit. This is because it is a fairly inexpensive upgrade and brewers truly begin to understand the importance of yeast and yeast health.
A yeast starter kit is very basic and typically consists of dried malt extract and an Erlenmeyer flask. They can also include yeast nutrient such as Fermax. When used in conjunction with a magnetic stir plate, these components can help propagate liquid yeast to reach a much higher concentration without having to buy multiple packages of yeast, which can be expensive.
At a higher cell concentration, activation will begin more quickly and you will be able to achieve a more complete fermentation making for a higher quality beer. So you’re probably asking yourself how you can use a yeast starter, right? Well it’s actually very simple.
Making Your Own Yeast Starter
First thing to note is to be sure that you prepare the yeast starter at least 24 hours to pitching. So about a day before you plan on brewing.
First, fill a pot of water about halfway and get it to a boil. Then pour a pint of water into the Erlenmeyer flask, place the flask into the boiling pot of water. This is known as the double boiler method and greatly reduces the risk of breakage by avoiding direct contact with the flask and the heat element. An even heat source such as an open flame is a safer bet than an electric heating element, which can have hot spots, but the double boiler method really is your best bet.
Bring the water within the flask to a boil then carefully pour in half a cup of dried malt extract (DME). Be careful as the moisture rising out of the flask via steam can cause the DME to become very sticky. Do your best to pour it in quickly and cleanly while limiting the amount that sticks to the inside of the upper part of the flask. Boil the water and DME mixture for 10 minutes and then remove it from the heat source. Pour in yeast nutrient if you have it and prepare an ice bath.
Place the flask into the ice bath and bring the contents to room temperature. Unlike cooling a full brew pot of wort, chilling the yeast starter will only take a short amount of time. Once you’ve gotten the contents down to temperature pitch the activated yeast package into the flask. Then place a sanitized airlock into the top of the flask. If you do not have an extra airlock, you can use a sanitized foam stopper. You just want to be sure that CO2 gas can be released without letting outside contaminants in—just as you would when fermenting your batch of wort. Let the flask sit in a cool dark place to patiently await pitching time on brew day. If you really want to ensure that your yeast starter is ready, enlist the help of a magenetic stir plate. A stir plate keeps the mixture moving at all times by spinning a magnetic stir bar within the flask to create a vortex that keeps all contents evenly mixed and suspended.
When you think about it, a yeast starter is essentially like making a mini batch of beer as it contains water, sugar and yeast. By mixing these contents together, you’re creating a highly concentrated mini batch of wort that serves as the perfect primer for a larger batch of wort. By the time you pitch the mixture into the wort, the yeast cell count has doubled and has already been activated making the yeast cells ready and eager to consumer the sugars in the wort. If you’re asking what this means for your beer, simply put, a whole lot of good. Once you make the transition to yeast starters, you’ll probably never go back—so get to it!