Homebrew yeast management: tips, tricks and traps

Managing homebrew yeast is one of the pillars of making great beer.

Whether you are mixing tinned concentrates or running full mash brew rigs, all homebrew needs healthy and active yeast.

I’ve had a handful of homebrew failures over nearly two decades I’ve been making my own beer. All can be traced back to poor yeast management.

Either I didn’t prepare the yeast properly, it was too small a volume for the task or it was old and degraded.

I want you to make awesome homebrew so let’s get you skilled up in yeast management.

Why yeast management is important

Awesome homebrew needs proper yeast management.

Being burnt with bad homebrew made me take yeast management seriously.

It is the powerhouse behind the homebrewing process.

Show it some love and you’ll get great beer.

You’ll be a better homebrew if you focus on creating an environment that supports a healthy yeast community.

What does homebrew yeast do?

Yeast microbiology is a complicated topic, but essentially yeast eats sugars and makes carbon dioxide, alcohol and a few extra things.

There is a bit of science happening behind the scenes, but all you need to know is how to keep yeast happy. Give it what it needs and life will be great.

If you are interested in learning more about the science of yeast management, check out John Palmer’s excellent articles on the topic.

What is yeast exactly and how do I pick the right one?

Brewing yeast is actually a type of fungi. Saccharomyces cerevisiae to be specific.

It reproduces by splitting off smaller cells. Your job is the equivalent of dimming the lights and playing Barry White.

Rehydrated homebrew yeast ready for pitching.

This means creating:

  • an environment free from competing microbes

  • the right balance between yeast and wort volume when pitching

  • a growing medium rich in oxygen and nutrients

  • a temperate that supports yeast growth while minimizing bad tasting by-products.

These factors all mean yeast can do its job—multiplying to convert wort to a pleasant-tasting product we know and love as beer.

Ditch the freebie

Unfortunately the usual five-gram packet of yeast supplied with your tin of concentrated homebrew is probably not up to the job.

It’s old, been exposed to temperatures and there’s simply not enough of it. You need at least 11 grams per 6 gallon (23 liter) batch. 

Less than this gives bacteria and wild yeast a chance to step into the void and wreck your beer.

One of the simplest things you can do to improve your beer is spend a few bucks and buy a premium brewing yeast.

Liquid vs dry yeast

You can buy brewing yeasts in a dry or liquid format.

Liquid yeast have a broader range of styles, but I prefer dry yeast for simplicity and ease of use.

While there is a perception that dry yeasts are lower quality than liquid, this has not been my experience. Modern dry yeasts will give awesome results and are far simpler to use.

I use dried yeast exclusively with great results—happy mates and podium finishes in state and national homebrewing competitions.

Start with dry yeast. If you want to experiment move into liquid later.

Homebrew yeast styles

There are dozens of different strains homebrewing yeasts. Many are slight variations and others will give you a particularly distinct beer (such a weizen or Belguim ale varieties).

When we pick yeast for our beer, we are making a decision about what our beer will look and taste like. Yeast can contributes up to thirty per cent of the overall flavor profile.

We inoculate our wort with our yeast of choice, then give it time and temperature. Beer comes out the other side.

Yeast choices

Pick your target style of beer and choose your yeast based on this.

Homebrew yeast manufacturers have handy references to help you make your selection. Here are a few:

If you want to reuse your yeast, I suggest using a versatile neutral strain like Safale US05 or Danstar Nottingham. You can brew a wide range of styles with the one variety.

No baking yeast unless you are making bread.

Ales and lager yeasts

You have many strains of brewing yeast at your disposal, but all can be classified as either ale or lager.

Whether you use one or the other depends on the type of beer you are trying to make and your ambient brewing temperature.

Ales work at higher temperatures and ferment in the top part of your wort. The results are generally earthy and wholesome.

So like an APA, IPA, bitter, porter, stout, wheat beer.

Lager yeasts are the sophisticated cousins. They work at lower temperatures, operate at the bottom of the wort, and are crisp, refreshing and clean. So think pilsners and lagers.

If you are still learning the ropes with homebrewing and yeast management, ale yeast is where I suggest you start.

The stronger flavors of ale styles can cover any slight flaws and they are simpler to ferment.

Neutral ale yeasts like US05 or Nottingham, coupled with the right recipe, can also result in a lager-ish beer.

What homebrew yeast needs

Homebrew yeast has a few demands to be met before it will deliver you delicious beer.

Homebrew yeast settled to the bottom of the fermenter.

Homebrew yeast settled to the bottom of the fermenter.

Time

Yeast needs enough time to ferment your wort and then clean up any off flavors. No more no less.

Check the status of fermentation with a hydrometer. Once finished, let the wort sit on the yeast cake for another five to seven days. The yeast will consume fermentation by-products during this time.

The wort will also clear as the yeast settles to the bottom, taking harsh tasting compounds with it.

The end result is a smoother, cleaner tasting beer.

Be warned though that leaving wort sitting on the yeast cake for long periods (over two weeks for ales, four for lagers) can lead to rubbery flavors. This is due to the yeast starting to consume itself (known as autolysis).

Temperature

Work at your yeast’s preferred temperature range. Too high will create off flavors and headache-causing fusel alcohols. Ouch.

Too low and your fermentation can stall. The implications can be more dangerous than a hangover—extra unfermented sugar in bottles can lead to explosions.

A pantry full of broken glass and sticky beer is not good for domestic bliss.

Volume

The five gram packet taped to the top of your homebrew tin is not enough cell mass to cleanly ferment your beer.

If you use 11 grams of healthy yeast for a six gallon (23 litre) batch, you are pitching enough yeast for it to do its job.

Any less means the yeast works too hard. It gets tired and sweaty, creating off flavors. You don’t want yeast sweat in your beer.

If you are reusing a yeast slurry, half a cup is enough for a solid fermentation.

Nutrients

Just like busy executives and multivitamins, wort also needs nutrients to perform at a high level.

Your fermentation will benefit from adding yeast nutrients to your wort. The result will be a cleaner, more fully fermented beer.

Kit and extract homebrew in particular will benefit from a nutrient boost.

When buying yeast nutrients, look for the light brown blends which have vitamins, minerals, zinc and other useful elements.

The white crystal variety is usually just diammonium phosphate, which will help but is not as complete.

Oxygen

Yeast consumes oxygen when replicating and building in volume. If there is not enough, fermentation can be sluggish, stall and lead to off-flavors.

You only really need to focus on increasing oxygen levels if you are boiling your wort, as boiling removes oxygen.

Kit homebrewers don’t need to worry as there is enough oxygen available in unboiled water.

If you need to increase your oxygen levels you can:

  • Stir violently with a sanitized spoon.

  • Use a sanitized stick blender and froth up your wort.

  • Inject air or oxygen with an aquarium pump and airstone.

How to prepare yeast correctly

Rehydrate dried homebrewing yeast

Before pitching dry yeast, you first need to rehydrate it with water that has been boiled and cooled.

If you add it dry, up to half of your yeast can be destroyed as the sugary wort solution floods the cell.

Rehydrating is simple to do:

  • First boil your kettle and let it cool to 95-104F (35-45C) for ales or 68-77F (20-25C) for lagers.

  • Clean and sanitize your packet of dried yeast, drinking glass, thermometer and scissors.

  • Pour a cup of the pre-boiled water into the glass and cover with sanitized plastic wrap.

  • Check the temperature to make sure it’s in the desired range.

  • Pour in your yeast and cover again.

  • Leave this for 15 minutes and then swirl around to mix in.

  • Leave for a further 15 minutes.

You will see the yeast has developed a creamy head and now can be safely pitched into your wort.

Dried homebrewing yeast after being sprinkled on boiled, cooled water.

Rehydrating success! The dried homebrew yeast has developed a thick creamy head.

You can now safely pitch your yeast into your wort or starter.

If you aren’t seeing any action, your yeast may be damaged. Break out your emergency yeast and start again.

Yeast starters

A starter is a small volume of wort that has been inoculated with your homebrewing yeast of choice.

Once it is actively fermenting, it can be pitched into your wort for a strong and healthy fermentation.

The advantages are that:

  • You know the yeast is viable before you pitch it into your brew.

  • There is shorter lag time, reducing the window for infections to establish.

  • Fermentation runs complete, leaving a clean tasting and fully fermented wort.

For ales make a one to two quart (1-2 liter) starter, for lagers two to four quarts (2-4 liters).

How to make a yeast starter

To make a yeast starter:

  • Rehydrate your dried yeast.

  • Boil your required amount of water in a saucepan and take off the heat.

  • Mix in dry malt extract at the ratio of three ounces (100 grams) of malt per one quart (1 liter) of water.

  • Continue to boil for 10 minutes, then seal and move to an ice bath to cool.

  • Sanitize a large bottle (twice the volume of your starter wort), thermometer and funnel.

  • When the wort temperature drops to the working range, funnel into the starter bottle.

  • Seal with sanitized plastic wrap and shake for 10 minutes.

  • Pitch your rehydrated yeast in the starter.

  • Seal again with sanitized plastic wrap and prick with a sanitized pin.

  • Pitch into your main wort once fermentation is active (6-24 hours).

You would normally make your starter the day before you brew.

Reusing yeast

Dried yeast is pretty cheap, but wouldn’t it be great to not rehydrate each time?

Every homebrewer should know how to safely reuse a yeast slurry. It’s really easy to reuse yeast from a batch of homebrew.

Just follow this process and pay close attention to cleaning and sanitizing:

  • The night before you bottling your homebrew, boil half a gallon (two liters) of water and let cool it down.

  • Bottle it in a clean and sanitized bottle and chill it in the fridge.

  • The next day bottle or keg your beer as normal, making sure to drain all liquid off the yeast cake.

  • Tip in your chilled water and swirl around to mix in the yeast.

  • Leave for five minutes for the solids to settle.

  • Then drain into cleaned and sanitized plastic bottles.

Reusing homebrew yeast

Reusing homebrew yeast

Squeeze the air out of the bottle, refrigerate and re-use within a week or two. Never use glass, as yeast can continue to ferment and explode.

You’ll see a quick and solid fermentation as the yeast is big, healthy and fresh.

If you follow correct sanitation and process, you can reuse brewing yeast up to three times safely.

Homebrewing With Kits—The Beginner’s Guide

To help you master homebrewing with kits, I’ve put together a guide based on my experiences over the last two decades.

This is the information I wish I had when I started brewing. I hope it helps you make awesome homebrew.

Download your copy today.