Why Isn’t Milk Sweet, Even Thought It Contains Sugar?

If you’ve ever taken a look at the nutritional facts for milk, you might be surprised to find that the ruminant derived liquid contains a large amount of sugar. Sugar is sweet right? Then why is it that milk doesn’t taste sweet?

Scientists say that there are five different flavors that the human tongue can detect. These include sweet, salty, sour, umami, and bitter. These five basic flavor profiles form the basis for the taste of anything that you eat. Unique combinations of these flavors meld themselves together to form the final taste.

Not All Sugars Are Sweet

Sugar is actually a categorical nomenclature that umbrellas multiple different types of sugars. Many different types exist in nature including fructose, galactose, glucose, lactose, maltose, sucrose and xylose.

As it turns out, not every single type of sugar is actually sweet. And some compounds that are not even sugar in the first place taste sweet.

Scientists put together a scale of sweetness that measures different sugars relative to sucrose. Lactose, the type of sugar found in milk, rates very low on the scale of sweetness.

Some of the sweeteners listed on the scale are actually thousands of times sweeter than your average sugar. Neotame is an example of this fact. Though it’s chemical structure does not earn it a slot in the category of sugar, it is still extremely sweet.

Milk CAN Be Sweet

The sugar found in milk, lactose, is actually comprised of two different sugar molecules: Glucose and galactose. Glucose measures very high on the sweetness scale and as such will taste sweet if the bond between glucose and galactose that makes up lactose is broken.

This can actually be accomplished if you let milk sit in your mouth for long enough. Eventually you will notice that it becomes sweet as the bonds are slowly broken.

Another example of this is ultra pasteurized milk. It’s known for having a sweeter taste than typical conventional milk that is just pasteurized normally or not pasteurized at all. This is because the process of ultra pasteurization breaks the bond between glucose and galactose.

Milk IS Sweet To Some

Lastly, it should be noted that some people actually do perceive the taste of milk as sweet. There are individuals that taste milk as more of a sweet substance than others. There is likely some variation in taste buds between multiple people.