A Yoghurt Synthesis

Recipe time on Muscleguy’s blog. When I was back in NZ visiting my mother she served me some home made yoghurt with stewed plums. Not wishing to offend I had to have some, but I was most pleasantly surprised it was creamy, delicious and flavourful. I quizzed her on the method and was introduced to the EasyYo system which is very simple (and invented in NZ). You dissolve one of the starter sachets in water in one of their 1kg containers. Fit the red baffle in their big white thermos and fill to the top of the baffle with boiling water. Insert the yoghurt container, put the lid on then wait 8-9 hours and you have lovely yoghurt. There’s a variety of flavours and styles available too. Around here Holland&Barrett and an independent kitchenware shop sell them.

However there are two problems with it. The first is cost. Sachets cost around £2.70, they make a full 1kg of yoghurt which lasts 2 weeks in the fridge, but. The second is that as I’m lactose intolerant I found I only barely  tolerated it. Proper yoghurt should have very little lactose, the bacteria should have converted it to lactate (which is why yoghurt tastes sour, pleasantly so). Commercial yoghurts add milk powder to make them thicker but still be able to put just ‘milk’ on the ingredients list, especially the low fat ones but I suspect most of them. There’s a lot of milk powder needless to say in an EasyYo sachet. I needed a way to both cut the cost and lower the lactose.

In searching the web for online sources of the equipment I came across a website which detailed a way to start with milk and just use a proportion of the sachet as a starter culture, resealing the sachet for next time. Great I thought and proceeded to try it. The result was quite good, though not very well tolerated by me and not being in possession of a wide mouthed thermos, hard to get out of it. Not wanting to buy a 1 litre wide mouthed thermos and having the EasyYo gear and needing to lower the lactose all combined to a necessity which gave birth to invention. A synthesis of the two methods, and very low lactose to boot. Here it is:

As Yobrew’s website does I heat the milk to 88 – 90C in a 1litre jug in the microwave (13-15min on average on high). For my yoghurt I use a 50/50 mix of whole normal (blue top) milk and whole LactoFree milk. Any lower % of normal milk and the yoghurt is runnier indicating 50/50 is optimal. Then the yoghurt goes into the thermos prewarmed with boiling water for 20min. Holding it at this temperature is supposed to inhibit the curds and whey from separating too much. Now is where my method diverges, I found the method of cooling clunky and inefficient, which in itself is an infection risk as the milk spends a lot of time at incubation temperatures. To use the milk in the EasyYo gear I also needed it at around 20C. Below is the setup I came up with. I usually use a larger plate to cover it but used a stand-in for photographic clarity 😉

Yoghurt Cooler

The 1litre pyrex jug the milk is heated in the microwave in is redeployed to contain the milk for cooling. It is kept covered by the plate in the interim. It sits in a large pyrex casserole which itself sits in a large pyrex mixing bowl. A tray full of ice cubes is in the lower part and another in the upper. The cold tap is run until the water is as cold as it’s going to get and the two compartments topped up. The timer is set for 15-20min by which time the milk is around 37C and the top ice cubes are gone and the water warm. Lift out the jug and replace the water with cold, no more ice is necessary though you could add more if you wanted. Another 15-20min (depending on ambient temperature) later and it’s 20-21C and usable. It is mixed with 1/4 cup of EasyYo Greek style starter in the EasyYo 1kg container and placed with the boiling water in their big white thermos. I like to flavour it with 1 1/2 teaspoons of vanilla extract, makes it taste sweeter with no extra sugar.

Cooling the milk this way is much faster and with the milk covered perfectly safe. We have kept the yoghurt for up to 2 weeks with no problems. If you had a copper cooling coil for home brew you could use that to cool the milk even faster. The outer bowl is simply to increase the mass of cold water and because the jug doesn’t fit in it without the casserole. The principle could be varied with a variety of containers. Instead of ice cubes you could run the cold tap (well off to the side of the jug) letting the water overflow and occasionally stir the milk. Any variant is going to faster than the Yobrew method of inverting just the neck of a plastic water bottle in the thermos.

The yoghurt is thick, creamy and delicious and I tolerate it very well. I use it in Gluten Free baking and making lactose free icecreams and it’s great.

My wife is not left out. She needs low fat yoghurt and is not lactose intolerant and likes real fruit in it. So for her I use 0.5% (red top) milk as above except that along with the 1/4 cup of starter I add 1/3 cup of skim milk powder to make it thick. When it’s made I take some fruit (blueberries, raspberries, cherries) fresh or frozen and make a compote from some of them with a bit of sugar, lemon juice and a capful of brandy (cheap for cooking). Leaving it macerate for up to an hour helps. Then heat at a low heat until the fruit begins to break down. Put a sieve over a bowl, put the compote in it and using the back of a spoon (metal, wooden or silicone) press the juice out and scraping it off the underside of the sieve. Combine with the rest of the fruit and in a large bowl mix into the yoghurt before returning to the 1kg container. My wife says it’s some of the nicest yoghurt she has ever tasted.

So what do you need for this?

  • 1 litre Pyrex jug, though a bowl would do the milk would be hard to pour out of it. And a plate to cover it.
  • 1 litre thermos though I suppose two 500ml thermoses could be used.
  • Large casserole and bowl with at least two trays of ice cubes.
  • EasyYo sachet
  • Skim milk powder for normal low fat yoghurt
  • EasyYo container and thermos (very reasonably priced as a unit)
  • Easy read electronic thermometer. We got ours from Nisbets for sugar work.
  • A timer
  • A kettle
  • Flavourings as per personal preference.

Heat in microwave in jug 13-15min until 88-90C. Transfer to preheated thermos and hold for 20min. Cool 30-40min total in double ice cooler. Add starter and possibly milk powder to milk. Stir and shake. Insert in EasyYo thermos with boiling water. Wait 8-9 hours.

If you start just after lunch you can put the yoghurt to cool in the fridge overnight just before bed. Or you can do it in an evening and leave it to incubate overnight. There is not much to do, it’s mostly just setting a timer and doing something else.

You get at least 6 X 1/4 cup starters out of an EasyYo sachet. So there’s just the cost of the milk and the electricity to add to 45p for 1kg of delicious low fat or almost lactose free yoghurt.

Hat tip to Yobrew for the method and absolutely no criticism is intended for the method other than the cooling. A good source of information generally as well. Also to my wife for the picture of my cooling set up.

Addendum: After a recent trial instead of vanilla extract and for greater depth of flavour take half a vanilla pod, slit it and scrape out the seeds. Add both to the milk while heating and leave to steep in the thermos. Run it through a sieve as you pour into the jug for cooling. Stirring the milk into a vortex sediments most of the unstrained seeds in the bottom where they can be left behind.