Q. What is the difference between Greek yoghurt and natural yoghurt?

A.   Greek yoghurt is higher in fat than standard plain or natural yogurt and is considerably thicker. It generally has around 8 to 10 per cent fat compared to 4 per cent for normal plain yoghurt.

I like to use it as a replacement for cream or sour cream (35 per cent fat) in recipes where you'd normally finish off with cream such as pumpkin soup or beef stroganoff.

It also works well as a lower-fat accompaniment to desserts like apple crumble or summer berry fruits - it's not low-fat but healthier and lighter than the usual whipped cream or double-fat ice cream.

It is made by straining through muslin or a cloth or paper or some sort of filter, which removes the liquid whey and leaves the final yoghurt thicker and more 'creamy' without extra fat. You get a consistency similar to sour cream or mascarpone, while retaining yoghurt's distinctive sour taste.

Some brands of Greek yoghurt add extra cream or powdered milk (milk solids) or start off by boiling off some of the water content in the milk, all of which reduces the water content and increases that thick richer mouthfeel.

In Greece, strained yoghurt, like yoghurt in general, is traditionally made from sheep's milk. Here in Australia, we use cow's milk instead, which is why you'll see it called "Greek-style" yoghurt.

I love Greek yoghurt in the kitchen

Greek yoghurt is easy as it doesn't separate or curdle when you cook it so doesn't need to be thickened with cornflour first.

Greek yogurt is a great addition to a healthy kitchen to thicken and finish off many dishes.

At say 10 per cent fat, it still has less than sour cream or cream which comes in at 35 per cent fat or lower at 18 per cent for the light types.

If you have ever had tzatziki made from regular yoghurt, you probably found it thin and watery. On the other hand, tzatziki made with Greek Yogurt is thicker and smoother. And a real treat, as I can verify from my many tzatziki appetizers on the Greek Islands!

Yes you can buy low-fat Greek-style yoghurt which has less than 3 per cent fat (like all foods labelled as 'low-fat') yet a thicker texture. However I prefer the 'whole food' concept of regular-fat yoghurt so buy the regular version.

I like to use Black Swan or Harris Farm Greek yoghurt with my muesli and fruit at breakfast and to thicken a curry or stroganoff.

The problem of disposal of the whey

The process of making Greek yoghurt starts with THREE or more litres of milk to create ONE litre of yoghurt. That's a 3 to 1 reduction in volume which creates a lot of excess whey to be disposed of. The whey is quite acidic and so can't be dumped into lakes or rivers as the acidity causes potential problems to the fish and plant life.  Farmers use some of the whey to feed animals (but there's a limit before it upsets their digestive systems) or as a nutritious fertiliser. But with the rapid rise in popularity of Greek yoghurts, there's now an excess of whey to dispose of.  And that's a huge problem for yoghurt makers.

Much research is looking into ways to convert and/or utilise the components of acid whey.  But until these become commercially viable, there's still the problem of the inefficiency of traditional Greek yoghurt-making techniques which are proving unsustainable for the environment as well as for business. The dairy industry is on the hunt for ways to figure this out.