This is a quick guide on how to grow up the yeast from the yeast bank to the amounts you require for a brew-day. When you order yeast from the bank you will receive a 5 ml culture of yeast, which you will need to step-up into useable amounts before you brew. Below are descriptions of how to grow up your yeast using either a stirplate+flask, or using a pop bottle.

Note: This process takes 5-7 days, so you need to plan your brew schedule accordingly.

Note: If you intend to store the yeast for more than a few days, I strongly recommend that you prepare the first starter (300 ml starter) and store that - it will be more stable than the 5ml culture.

Materials Required - Stirplate Method

  • DME or 1.040 wort
  • Flask (ideally 1L and 2L sizes)
  • Stirbar
  • Stirplate

Materials Required - Pop Bottle Method

  • DME or 1.040 wort
  • Clean and sanitised 2L pop bottle, with cap
  • Sanitised funnel

Stirplate Method

Days 1-3:

  1. Prepare 300 mL of 1.040 wort:
    • If using DME, dissolve 33g of DME into 300 ml of water.
    • If using wort prepared earlier, dilute to 1.040
  2. Place the wort& stirbar into your flask, and cap the flask with tinfoil. Bring to a gentle boil and boil for 10 minutes to sanitize.
  3. Cool the wort to room temperature.
  4. Carefully open the tube of yeast - it can be pressurised, so take care to prevent spillage. Immediately dump the yeast into the flask, being careful to not touch the tube to the flask (this can lead to contamination).
  5. Place the flask on your stirplate, in a warm location (20-25C is ideal), and stir at a medium speed such that a vortex is formed in the wort without significant splashing.
  6. Allow starter to grow for 2-3 days, until wort is turbid.

Days 3-5:

  1. If desired, place the flask of yeast into the fridge; this can be stored in this fashion for upto 1 month. In addition, the spent wort can be decanted from the yeast for the next starter step.
  2. Prepare fresh 1.040 wort, as above, preparing between 1.0L (109g DME; will produce ~200 billion yeast) to 3L (330g DMEl will produce ~500 billion yeast).
    • If you have a second, larger flask, prepare the wort in the flask and, once cooled, dump the 300 ml starter (or decanted yeast from this starter) into the new flask.
    • If you lack a second flask, prepare wort in a saucepan, and once cooled, add to the 300 ml starter to your original flask
  3. Place the flask on your stirplate and stir as above for an additional 2-3 days.
  4. Your yeast is now ready; it can either be pitched directly into a beer or you can allow the yeast to settle for 1-2 days and decant the spent wort prior to pitching the yeast.

Pop Bottle Method

Note: It is critical that you carefully clean and sanitise your pop bottle and funnel immediately before starting this procedure

Note: This method does not produce as much yeast, per volume of starter, as a stirplate, so additional steps may be required.

Days 1-3:

  1. Prepare 300 ml of wort as described in the "Stirplate Method", above
  2. Once cooled, used a sanitised funnel to transfer the wort to your pop bottle.
  3. Tightly cap the bottle and shake vigorously for 5 minutes.
  4. Carefully open the tube of yeast - it can be pressurised, so take care to prevent spillage. Remove the cap from the pop bottle and immediately dump in the yeast, being careful to not touch the tube to the bottle (this can lead to contamination).
  5. Place the cap loosely on the bottle (loose enough that air can escape) and place in a warm location (20-25C is ideal)
  6. 3-4 times each day:
    • Squeeze the bottle to push out the air, then let the bottle re-expand to fill it with fresh air
    • Tighten the cap, and shake vigorously for 2-3 minutes
    • Loosen the cap so the bottle can breath
  7. Allow starter to grow for 2-3 days, until wort is turbid.
  8. Cap the bottle tightly and place it in the fridge; this can be stored in this fashion for upto 1 month, and you will need to decant the spent media prior to the next step.

Days 3-5:

  1. Prepare an additional 1.75 L of 1.040 wort (190g DME). Boil the wort to sanitise and cool.
  2. Carefully decant the spent wort from the bottle, leaving the yeast behind
  3. Using a sanitised funnel, add the new & cooled wort to the yeast. Cap the bottle and shake vigorously for several minutes.
  4. Place in a warm location for a few days, shaking the bottle frequently as described above.
  5. When complete, pour the starter directly into your wort, or let the yeast settle to decant
  6. The above method will produce ~35 billion yeast; if more yeast are needed decant the spent wort and add fresh wort, as described above. Predicted yeast yields can be found in the table below.


Step/Volume   # Yeast at End
300 mL  2.6 billion
1.75L #1  35 billion
1.75L #2  138 billion
1.75L #3  292 billion

Note: yeast numbers assume yeast is sedimented and the spent wort completely decanted between each step

Here is a video demonstrating the bottle method:

Hints & Tips

  • Adding yeast nutrient at ~2x the manufacturers recommended dose increases yeast yield by 25-30%
  • Add ~5 drops of Fermcap-S to all starters to prevent boil-overs and excessive foaming of the starter
  • Decanting yeast between steps increases yield
  • Yeast ferment best if there is less than 5 days between the completion of the starter and the pitching of the yeast into the beer
  • A cheap way to make wort is simply to prepare an extra few litres of wort on a normal brewday, remove the extra before your boil, dilute to 1.040, and store that wort in a freezer or can it using a pressure cooker

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