Fresh Yoghurt in Flask

This is a favourite with both the crew for breakfast, usually as a dollop on top of a melange of rolled oats, cornflakes and dried fruit but also mixed with a little cucumber and salt as an accompaniament to a curry.

You will need a wide mouthed vacuum flask that will take around a litre or a litre and a half of liquid, a ballon whisk is handy to mix things and a small jug to fill the flask with. To start your first batch use a small pot of plain live yoghurt. I try to buy greek style but have made great yoghurt from a cheap low-fat pot.

I use a sugar thermometer to check the temperature accurately but you can rely on your finger to check the milk mixture is cool enough to add the yoghurt. It should be below 50 degrees ie comfortable enough to put a (clean) finger in, cooler doesn’t matter but hotter will kill the bacteria.

  • Full cream milk powder sufficient to make 1 litre plus one extra tablespoon
  • One litre of water
  • Starter yoghurt brought to room temperature – either some saved from your previous batch or a small pot of plain yoghurt

First of all everything should be clean, I usually get all the equipment out- saucepan, whisk, jug, measuring spoon, flask, thermometer – then pour boiling water into the saucepan and dunk everything into it before I start.

In the pan place the water and set to heat up gently

Whisk in the milk powder whilst the water is warming up. You need the milk to get to above 60 deg C ie so bubbles are just forming around the edge of the pan.

Remove the pan from the heat and leave to cool until the milk is below 50 degrees C (ie is 49 deg or lower). This is quicker if you move the pan completely away from the still warm hob!

Once cooled whisk in the yoghurt and transfer the resulting liquid culture to the vacuum flask. The jug makes this much less messy but I still do this over the galley sink in case the boat lurches.

Seal up the flask and leave on a galley shelf for 24 hours. Then tip or spoon out into a clean watertight container and place in the fridge to chill. Sometimes the yoghurt will very very thick other times it is as runny as shop bought stuff, see tips below.


If it smells like old socks when you open the flask it is beyond saving – tip it away and start again ensuring you really have clean utensils.

If it is ‘stringy’ then you were probably over generous with the milk powder – try using slightly less next time.

If over time your batches become progressively less thick then its probably time to find a new starter pot.

New Zealand Fernleaf Full Cream milk powder makes excellent yoghurt!