It's our daily drink... now more affordable than ever.
"Cheap milk is a good thing for consumers" says Ingrid Just from consumer group Choice.
But is YOUR glass of generic brand milk really only HALF full?
According to Braeden Lord, CEO of Aussie Farmers Direct, "an unsustainable retail price forces processors to take short cuts to produce milk at a sustainable pricing level"
Up to 12 percent of your carton could be permeate - a watery by-product made up of waste of other dairy production.
The MORE permeate mixed in, the less farm milk needed, the cheaper each bottle is to produce.
"Not only are the poor farmers getting the injustice of this, but consumers are unaware of the adulteration of the milk" says Lord.
Ian Halliday from Dairy Australia says permeate occurs naturally in ALL milk... but admits processors adjust milk to standardise levels of components such as fat and protein.
"All milk is safe and nutritious and by varying the levels of components within milk products it just provides that consistency on a day to day basis that consumers are looking for.
The organisation claims processors don't ADD extra permeate, however some companies including National Foods - have admitted using it to top up generic milks and the popular Pura range.
Dairy Australia also denies there's any difference between the quality of premium and generic brand milks.
"Do generic brand milks have a higher level of permeate? no they don't"
So how can you tell how much permeate is in your milk? Well according to consumer group Choice - it's near impossible.
"You can't taste permeate. You can't test for permeate."
If its so well hidden does it really matter?
"It doesn't necessarily mean if you are buying a cheaper milk variety that you are necessarily getting a poorer milk product" says Choice.
But which milk tastes the best? We thought we'd let your taste buds decide. We hit the streets to find out which milk you prefer.
Today our participants are blindly tasting two full cream milks. One is a brand name, the other a generic with added permeate.
Both should taste the same.
First, we give them the premium brand milk.
"It's creamy, creamy yeah" said one respondent. "It tastes like normal milk." "It tastes quite creamy" said two others.
Then, they try the generic.
"It seems like it's watered down" said one respondent. "How does it compare to the other milk you tried? pretty crappy really. that one is definitely a lot cremier" said another.
Compare the labels... and these two generic and premium brand milks appear the same... yet our taste testers could tell the difference.
As for taste... those that preferred the more highly permeated generic milk, usually drink skim, and likened it to that.
Consumer group Choice conducted their own taste testing - their respondents claimed they couldn't tell any difference between the premium and generic.
Ingrid Just from Choice... "it was a bit of a surprise but then if you look at the nutritional profiles of both they are actually very similar"
We also put the generic and premium milks we used for our taste test to a froth test.
Although both milks are labelled to contain the same components, it took 20 seconds longer for the generic brand one to froth.
It does contain a higher level of permeate, although its not specified on the label.
Dairy Australia says "we are very happy with the labelling in Australia. If you look at a carton of milk I think it has good descriptors of what is contained in milk"
Aussie Farmers Direct disagree and say permeate levels should be marked clearly on each bottle.
"I think the Australian consumer deserves to know what goes into their product. In the same way you can choose between caged eggs and free range eggs, squeezed juice and one that's made from concentrate. It's the same with milk, if milk has been adjusted by adding permeate to it, why not include it on the label?"
The debate has spawned a new range of milk on our supermarket shelves. Several companies including Aussie Farmers Direct are now making permeate free milk.
"It contains no additives, there's no permeate, no one is playing with the additives. It's just good quality Australian milk" says Braeden Lord.
While it appears to affect consistency in taste and froth ... permeate is in no way harmful to our health.
"Adding permeate isn't bad for you, but it's something that should be labelled"
In the supermarket aisle.... it really comes down to preference... and price
"Everyone is always going to have their preference" says Ingrid Just from Choice.
The advice to consumers is pick what milk you want and drink that.
It's probably the only way to ensure you'll drink a glass and a half.