Yeasts are living organisms and react to their environment based on various conditions (e.g. temperature, nutrients, chemicals).
You want your yeast to populate the wort as quickly as possible to prevent other organisms from taking over.
By preparing a yeast starter, you give your brewing yeast a legs up on the competition and save money at the same time because the alternative is to add multiple packages of expensive liquid yeast.
You basically want to create an environment for the yeast to grow ahead of your brew session. You can use light dried malt extract to build this environment. Don’t use cane sugar because the byproduct of the yeast creates a cidery flavour (unless of course you want a cidery flavour to your beer – then go nuts!).
- Brew pot that can hold 4-5L
- Glass container (a couple of growlers or a 1-gallon jug will do) that can hold around 2L plus room for CO2 foam
- 200g of light dried malt extract (LDME)
- 2L water
- Boil 200g of LDME in 2L of water for 30 minutes
- Add cold water to brewpot to cool down the wort to yeast pitching temperature
- Add cool wort to glass container and shake to introduce oxygen
- Pitch the yeast and wait 24 hours
- Optional: shake from time to time throughout the 24 hour period to release carbon dioxide and add more oxygen
- Two Options:
- Brew day 24-hours later: Subtract the amount of LDME used from your recipe.Pitch your yeast starter into your brew at the yeast pitching stage.
- Store your yeast starter 48 hours later (or whenever the yeast activity essentially stops): Pour the yeast starter into sanitized, sealed containers (small 750ml grumblers, mason jars) and put them in the fridge. Remove a yeast starter container on brew day and pour as much of the old beer off the top of the yeast sendiment as possible (without disturbing the yeast or pouring any out). Before the boil, add some wort to the container to re-active the yeast.