There are many guides on the internet about how to make a yeast starter for homebrewers. The goal of this guide is to give you a more practical approach on how to maximize yeast propagation, minimize costs or minimize effort. The method you choose will depend on your goals and your style. Maybe you want to make the most healthy yeast you can to brew that crisp lager. Maybe you only have a few minutes to spare and need to get on with it. Maybe you are on a budget. This guide offers three approaches to building yeast starters to meet any need.

Maximize the yeast count and health

This is the approach to take if you are trying to perfect a recipe, need extra yeast for a big beer or like to nerd out about yeast. It’s definitely the most sciency and your family/friends will ask you what science project you are doing. This is because it involves a large flask and a stir plate.

Pros: Makes lots of yeast with low risk of infection/contamination

Cons: Requires the right equipment plus time and effort

Equipment:

Steps:

  1. Using an online calculator, figure out how much DME you need and measure it out. For a 2L flask, a good size is 1.5L which requires ~150g of DME.
  2. Mix the water, DME and a pinch of yeast nutrient in the flask and mix.
  3. Put directly on the stove (gas only) and boil for 5 minutes.
  4. Cool in the sink until at room temp using an ice bath and laser thermometer.
  5. While cooling, sanitize a square of foil, the stir bar and the outside of the yeast packet.
  6. Once cool, cover the flask with the foil and shake vigorously to oxygenate the wort.
  7. Add the stir bar and yeast to the flask and recover with the foil.
  8. Place on the stir plate in a spot with limited light exposure and consistent temps near your target brew temp. Turn on.
  9. Wait 2-3 days until fermentation has completed and then put in the fridge at least overnight to crash out the yeast.
  10. On brew day, pour off most of the liquid and resuspend the yeast for pitching.

As you can see, this method is very involved. It usually takes an hour or more to boil and cool the wort in step 4. It also requires a lot of equipment that can run over $100. However for maximizing cell count, there isn’t a great replacement for the stir plate setup. Overall this method will maximize the yeast count and ensure they are super healthy and ready to make beer.

Minimize Costs

This approach is much more financially viable and can be done with household items. You probably won’t get the most yeast with this method, but it won’t require much upfront investment.

Equipment:

  • Any plastic or glass container you can find such as:
    • Mason jar
    • Used pasta sauce jar
    • Soda bottle
  • Large pot
  • Aluminum foil
  • DME
  • Measuring cup
  • Water
  • Ice
  • Sanitizer such as star san.
  • Bakers yeast (optional)

Steps:

  1. Using an online calculator, figure out how much DME you need and measure it out. A good size is 1.5L which requires ~150g of DME.
  2. Mix the water, DME and a pinch of baker’s yeast in the pot.
  3. Put the pot on the stove and boil for 5 minutes.
  4. Cover and cool in the sink until at room temp using an ice bath until at room temp. You can avoid using a thermometer by simply waiting longer until the wort is cool.
  5. While cooling, sanitize a square of foil, the container and the outside of the yeast packet.
  6. Once cool, carefully transfer the wort to the container.
  7. Cover the container with the foil and shake vigorously to oxygenate the wort.
  8. Add the yeast to the flask and recover with the foil.
  9. Place the container in a spot with limited light exposure and consistent temps near your target brew temp.
  10. Swirl as often as possible.
  11. Wait 2-3 days until fermentation has completed and then put in the fridge at least overnight to crash out the yeast.
  12. On brew day, pour off most of the liquid and resuspend the yeast for pitching.

This method is essentially the same as the first except that you have to boil and cool the wort in a pot before transferring. This adds time and cleaning plus the added risk of infection.

Minimize Effort

Many homebrewers end up here after a while, mainly due to laziness increasing over time. The most annoying part about the first two approaches is that you have to boil and cool the wort. To avoid this step, there are two main ways to acquire sterile wort: use a pre-made wort like Proper Starter, or to simply use wort from your brew day. The former option is less disruptive to your process but is more expensive. The latter is “free” but requires some changes to how you pitch yeast.

Proper Starter

Proper Starter is pre-made canned wort designed specifically to be used for yeast starters. Simply sanitize your container, yeast packet and top of the Proper Starter can. Mix together in the container. If you have a stir plate, you can use that as well.

Proper starter can

MoreBeer

Amazon

Using wort from brew day

Instead of shelling out $$$ on pre-canned wort, you can use wort from a readily available source, your brew day. The idea here is that you take some wort from your brew day in your yeast starter and pitch it 1-3 days later. The main drawback is that the rest of your wort has to sit in the fermentor without yeast for that time, increasing the risk of infection. There is a whole group of no-chill brewers out there who do this anyways, so it’s a proven method.

Conclusion

Whether you want to optimize for time, effort or cost, there are several ways to create a yeast starter to fit the needs of any homebrewer.

Cheers!