By Lance Shaner
May 3, 2022
Most homebrewers know that one of the best ways for increasing your yeast count for high gravity beers — or reviving old yeast — is to make a starter. Beginning homebrewers might be intimidated by the thought of becoming home microbiologists, but with a little bit of guidance, we hope to demonstrate that it’s not so hard! This guide will take you through various methods of creating an ale or lager yeast starter, from the simplest and most cost-effective to a professional-grade starter.
Once you’ve determined your preferred method for preparing your starter, you can use it to create a Lactobacillus or Brettanomyces starter.
Milk jug starter
Certainly the most cost-effective way to make a starter, an empty milk jug or juice container can be used in place of an Erlenmeyer flask. However, this method will not yield the highest cell count possible. Recommended for beginners.
Materials needed:
- Sanitizing solution (e.g., Star San)
- Milk jug or juice container (2 liter or ½ gallon minimum)
- Dry malt extract (100g, 3.5oz, ½ cup)
- 1L water (33.8oz)
- aluminum foil
- small pot for boiling malt extract
Step 1: Rinse your milk jug or juice container as thoroughly as possible.
Step 2: Fill the milk jug/container with sanitizer solution.
Step 3: Boil 100 grams dry malt extract in 1L of water for 15 minutes. Let cool, covered, until wort reaches room temperature.
Step 4: Remove sanitizing solution from milk jug/container and carefully pour wort into container.
Step 5: Carefully pour yeast pack into container, cover container with sanitized foil, and shake vigorously to aerate.
Step 6: Shake vigorously intermittently for 24 – 48 hours (it’s not really possible to shake too much).
Step 7: Pitch yeast into fermentor full of wort.
Flask starter (no stir plate or pressure cooker)
The significant advantage this method has over the milk jug starter is that your starter vessel (a borosilicate Erlenmeyer flask) is effectively sterilized along with the wort inside it. Borosilicate also handles temperature shock much better than regular glass without shattering, but be careful! These flasks will get very hot when you heat your wort. Not recommended for beginners.
Materials needed:
- Sanitizing solution (e.g., Star San)
- 2L borosilicate Erlenmeyer flask
- Dry malt extract (100g, 3.5oz, ½ cup)
- 1L water
- aluminum foil
Step 1: Add 100 grams dry malt extract and 1L of water to flask. Swirl until extract is reasonably dissolved.
Step 2: Bring to boil and maintain boil for 15 minutes. Cover with foil and let cool until wort reaches room temperature. Borosilicate flasks can handle direct flame but will get very hot — be extremely careful when handling these flasks. Use pot holders or other heat protection.
Step 3: Carefully pour yeast pack into container, cover container with sanitized foil, and shake vigorously to aerate.
Step 4: Shake vigorously intermittently for 24 – 48 hours (it’s not really possible to shake too much).
Step 5: Pitch yeast into fermentor full of wort.
Flask starter (Propper Starter and stir plate)
An easy and convenient way to make yeast starters because you can skip the wort sterilization step — using Propper Starter and a stir plate further simplify the process. Good for beginners with the required materials.
Materials needed:
- Sanitizing solution (e.g., Star San)
- 2L borosilicate Erlenmeyer flask
- Propper Starter can (16oz)
- 16oz (0.5L) bottled, distilled, or boiled (and cooled) water
- aluminum foil
- stir plate
- stir bar
Step 1: Sanitize 2L flask, stir bar, top of Propper Starter can, and yeast pack.
Step 2: Swirl and open can of Propper Starter. Pour contents into flask.
Step 3: Add 16oz of bottled, distilled, or boiled (and cooled) water to flask.
Step 4: Pitch yeast and swirl flask to mix.
Step 5: Add stir bar to flask, cover flask with sanitized foil, and mix on stir plate for 24 hours.
Flask starter (stir plate and pressure cooker)
The gold standard of yeast starters. Using this technique will result in sterile starting wort and highest cell counts. This is the most advanced method covered here.
Materials needed:
- 2L borosilicate Erlenmeyer flask
- Dry malt extract (100g, 3.5oz, ½ cup)
- 1L water
- aluminum foil
- pressure cooker large enough to hold 2L flask
- stir plate
- stir bar
Step 1: Add 100 grams dry malt extract, stir bar, and 1L of water to flask. Swirl until extract is reasonably dissolved. Place foil-topped flask in pressure cooker and fill with water to level of wort in flask.
Step 2: Follow instructions for your particular pressure cooker. Bring to 15psi and maintain for 15 minutes. Let pressure cooker depressurize until flask can be removed from pressure cooker and allow to cool until wort reaches room temperature.
Step 3: Carefully pour yeast pack into container, put foil back on flask, and place on stir plate. Turn on stir plate.
Step 4: Allow to spin for 24 – 48 hours (24 hours is plenty if culture is healthy).
Step 5: Pitch yeast into fermentor full of wort.
Considerations
A 1.040 (10°P) wort starter made from DME should have a copper-colored, relatively clear appearance (with some chunks from a protein break). As the starter grows, it should get progressively creamy in appearance. Depending on the flocculation characteristics of your strain, a starter nearing the end of its growth cycle can look different. For example, British Ale VIII (OYL-016) is extremely flocculent and takes on the appearance of egg drop soup as the yeast clumps together when the malt sugars are fully consumed. Within minutes, the yeast will drop to the bottom when the stir plate is turned off. In contrast, Tropical IPA (OYL-200) is extremely non-flocculent and will have a uniform creamy appearance and the yeast will take a considerable amount of time to drop to the bottom of the flask.
Another decision to make is whether to decant the spent growth medium before pitching your yeast. It depends on many factors:
- Are you brewing a very pale lager with a large starter?
It might be a good idea to crash and decant because the oxidized starter beer could conceivably be perceived in the final product.
- Did you make a 1L starter for a 5‑gallon batch of a modest starting gravity stout (~1.040 – 1.060/~10 – 15°P)?
Assuming you’re making a 5‑gallon batch, the starter would be diluted 1:20 into the wort. It’s unlikely the starter beer will be perceived in the final product, so decanting is probably not necessary in this case.
Depending on the flocculation/sedimentation characteristics of your yeast, be sure to factor in the amount of time needed to crash the yeast to the bottom of the flask if your plan is to decant. It’s not a bad idea to plan for your starter to be finished growing the day before your brew day if you’re using a low-flocculating strain in order to provide adequate time for a cold crash in your refrigerator.
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