Licking the Salt Stone

Q: Dear 100 Hour Board,

Why does watermelon taste sweeter when you put salt on it?

Georgia Inquisitive

A: Dear Peachy Keen on an Answer,

People do a lot of things with their watermelon. Some better than others. They eat it. Pickle the rinds. Cut into wedges, squares, balls and strips. Juice it. Salt it. Some even (so we've heard) drill a hole in it and pour libations therein. (The 100 Hour Board loves to shave it in thin slices and serve with cucumber slices with prosciutto and lemon olive oil. But we digress). We've even seen pictures of little kids with watermelon that is worn rather than eaten.

But why salt it?

The 100 Hour Board - in our infinite wisdom - will tell you the reasons, both the simple, the most likely and the probable. So sit back with a slice of pink and green, pull up a can for spittin' seeds and enjoy. (Just don't spill on the keyboard. IBM doesn't like the sticky keys.)

The short answer - salt doesn't make your watermelon sweeter, just seem that way. It works too with all sorts of fruits, especially: tomatoes, melons, pineapple, mangoes, papayas and even wine (again - so we hear). We'll give you the top three reason this works.

1. Seasoning. Salt is the ultimate season. (that's as seasoning not spring or fall) As a primary taste (along with sweet, bitter, sour and umami - the newly found one) it adds depth to things we eat. For a long time it was thought we had individual taste buds for each taste type. But currently, "electrophysiological evidence indicates that although some cells are especially responsive to specific types of stimulus, they also respond to other taste stimuli to varying degrees as well." To quote a recent cartoon rat. Think of taste like music, with each taste a layer that works in harmony to make a symphony. Salt is like a major bass note - supports a whole lot to make things tasty. Add a little salt, and things taste better. A little more and the full flavors come really out. A little more and it begins to get salty. Balance is the key. So a little salt on that melon will enhance the flavor as it plucks the strings of your taste bud.


2. Vacuoles. Plant cells contain little pockets inside that act as little storage depots. Some are temporary garbage dumps. In plants, they can be 90% of the volume in the cell. Plant vacuoles, especially in fruit cells designed to be tasty and enticing, are full of the sweet nectar we animals love. All those complex flavours, acids and the like fill those delicious bubbles. As we eat, these burst inside cells and fill our mouth with acids, sugars and other chemicals. The idea is that when we add salt, osmotic pressures (more salt on one side of the cell wall, can help lyse - break or drive out - the flavourful liquid. Thus the fruit is oozing with goodness sooner in the tasting process - before we need to chew it up. This is much like a fruit ripening and beginning to decompose to be tastier.


3. Balance. This is a little more touchy a reason - but important. We talked about strings on the taste chord. But balancing the sweet - sour, bitter - sweet, salty - acid, etc. balances are important. Fruits really need to get the sour/sweet thing right. In fact there is a lot of sour in unripe fruits to keep you away from them until they are ready. Then out comes the sweet big time. It seems that fruits with especially high sugar to acid ratios (a lot more sugar than acid) are well suited to salting. These include (with their ratio) grapes (80), melons (40-50), bananas (60), papaya (80) and even cactus pear (110). But there are exceptions: pineapple (6), strawberries (6) and grapefruit (8) which are served well by a salting - which may point to a different balance salt helps find. (Too much sugar or too little). Maybe that is why we typically leave apples (13), peaches (25) and plums (17) alone.

Odd mixes of chemicals really can bring out the best of tastes. Salt is just the beginning. So keep on eating melon with a shaker my friend. And open your melon mind to try it out on a couple other things. But don't be afraid of other things. Pure cocoa in a tomato sauce for example really helps bring out that non-acidic or sweet tomato flavour (umami! like glutamate).

A very hungry 100 Hour Board