How to make a yeast starter

Posted on 14th September 2020

Sometimes there is a need to make a yeast starter rather than direct pitching a a vile of yeast. In this blog we are looking at wet as opposed to dry yeast. With dry yeast there maybe instructions on the pack to rehydrate before pitching but this is not the same as making a yeast starter.

All of the wet yeast that we sell are designed to be direct pitched into 19 litres of wort but there are circumstances where you are making probably 23 litres ( 40 pints ), maybe the yeast is heading to its best before, maybe there was a delay in the delivery of or didn’t get put in the fridge right away. In all these circumstances a pitching multiple vials or making a yeast starter is advised.

The different yeast labs that we work with do differ in their approach so do read the individual instructions before purchasing however, there is a general theme that you can follow.

The reason to make a starter is:-

A) To ensure that the yeast is viable.

B) To grow enough yeast for your specific batch of wort.

c) To grow yeast into multiple pitches, this is make the most value from one vial of yeast.

The below instructions are taken from the Whitelabs website but will work just as well with all of our brands of liquid yeast.

“In a medium sauce pan, add 2 pints of water and 1/2 cup Dried Malt Extract (DME).  Mix well and boil the solution for about 10 minutes to sterilize. Cover and cool the pan to room temperature in an ice bath.  This will give you a wort of approximately 1.040 OG.  Keeping the Original Gravity low is important because you want to keep the yeast in its growth phase, rather than its fermentation phase.  The fermentation phase will create alcohol which can be toxic to yeast in high concentrations.

Pour the wort into a sanitized glass container (flask, growler, etc.) and pitch the vial of yeast.  Cover the top of the container with a sanitized piece of aluminum foil so that it is flush with the container, but will still allow CO2 to escape.  Vigorously shake or swirl the container to get as much oxygen dissolved in the solution as possible.  Keep the starter at room temperature for 12-18 hours on a magnetic stir plate, or occasionally shaking it to keep the solution aerated.

You probably won’t see any visible activity, but the yeast is busy taking up the oxygen and sugars in the solution and growing new cells.  After 18 hours, the yeast will have consumed all of the nutrients and oxygen in the starter.  Switch off the stir plate or discontinue shaking and it will form a milky white layer on the bottom of the container as the yeast flocculates.  If you are not planning on pitching the yeast right away, you can store it in the refrigerator with the foil still in place.

When you are ready to brew, decant off most (80%) of the clear liquid from the top, being careful not to disturb the yeast layer below.  Once the yeast and your wort are at approximately the same  temperature, rouse the starter yeast into suspension with the remaining malt solution and pitch the yeast slurry into your wort.”


A shortcut can be made by using a can of Proper Starter, no need to boil any malt extract, you just open the can, dilute with bottled water and pitch the vial.


Use the chart below to checkout starter size

If you have any concerns about the viability of your yeast then don’t pitch and hope, this could lead to a very bad day. Instead follow the steps and make a yeast starter, for certain at some point it will be needed and is a good skill for a brewer to have. Also, it can be fun cheating the system and getting multiple pitches from one vial of yeast.

1 thought on “How to make a yeast starter”

  1. John Pittman says:

    Great description, if i create the yeast starter should I assume then that I have enough for more than one 23 litre batch? I am looking at the malt Miller kit, which includes the stir plate, etc, if i pitch one can of the starter to say one pouch of kveik yeast, how many additional batches should I expect to get from one ‘mother’ pouch? In fermentation in general like beer, sourdough bread, kimchi, kefir etc, the idea of starters is to make multiple batches from one starter, replenishing the starter as needed.

    Just a note, in one sourdough class I took, the mother for the bakery was 13 years old, and still going strong in my home for the past three years.

Leave a Reply


Subscribe to our newsletter to be the first to hear about new products, special offers and seasonal discounts.