The expression “cool as a cucumber” was bound to exist. The cooler the better, in fact, as nothing beats a cold one straight out of the fridge. But even a warm cucumber, freshly picked in the middle of a hot field, can be gloriously refreshing. The impossibility of a cucumber gathering and stashing all that water is as cool as the hydration itself.

People make a big deal about the different kinds of tomatoes they can buy during tomato season, but the same can be done over cucumbers. The differences are more subtle, but no less enjoyable. Variations in flavor, water content, crispiness and how it explodes in your mouth all add up to myriad gastronomic experiences.

Discovering health benefits

Cucumbers are considered a physiologically “cooling” food in the Aryuvedic medical philosophy of India, where the plant is thought to have first been cultivated. I can’t comment on the physiology here, but I do know that if you cool your cucumbers first, they will be a cooling food. And beyond the relationship between cucumbers and temperature, cucumbers are proving potentially cool in other ways as well.

Pharmacological researchers have zeroed in on several chemical compounds found in cucumbers for potential medical applications. Many of these are found in cucumber seed extract, but interesting compounds have been isolated elsewhere in the fleshy fruit, such as the peel and the blossom end of the cucumber, also known as the bitter end, which contains cucurbitacin C, a toxin created by the plant to ward off predators like spider mites that attack the flowers. Chemically, cucurbitacin C is a steroid molecule, though it isn’t currently banned by any sports leagues, so it must not be much good in, you know, that department.

Nobody has gotten sick from too many cucumbers, but there have been several non-fatal cases of cucurbitacin C poisoning resulting from bitter melon, a relative of cucumber, and from eating unintentionally hybrid cucumbers, zucchini, squash, melon or other members of that same family, cucurbitacea, that have cross-pollinated in the compost pile or some other unexpected place.

At low doses, results are promising in many arenas, with cucurbitacin C showing potential anti-tumor, anti-diabetic, anti-atherosclerotic and anti-inflammatory activities.

The cosmetics industry, meanwhile, has latched onto some other molecules in cucumber seeds, promoting their ability to hydrate, elasticize and — you guessed it — cool and calm the skin.

Try ‘em all

Now is peak cucumber appreciation season at the farmers market, with each farmer’s every variety of cucumber all hitting. Last week I brought home five different varieties from three different vendors, and let the comparisons begin. The highlight was the “Chinese cucumber,” which had such a pale shade of green it was almost gray, with a thin, spiky skin like a pickling cuke and an explosive, watery crisp.

Another great cucumber is the Armenian, which is as delicious as it is enormous. And don’t sleep on the normal, plain-Jane-looking dark green slicing cucumbers. There are some really fine varieties out there.

There are all kinds of lovely recipes for fresh cucumbers, but if your goal is to compare and contrast, munching them straight out of the fridge is the way to go. It’s also a very enjoyable and refreshing thing to do.

And if that is too much chewing, I suggest putting your cukes in a Vitamix or similar high-speed blender with some ice cubes and whipping up some of this frothy, foamy, froamy cucumber ambrosia.

Cucumber Ambrosia

• 2 medium cukes (or one large)

• 4-8 ice cubes

• 1/4 lime

• 4 mint leaves

Slice the blossom ends of both cucumbers. If you can’t tell which end is which, slice them both off and nibble each end. Then you will know. If you want to remove any bitterness from the blossom end, rub the cut face of the bitter end against the cut face of the cucumber. Rub in a circular pattern, which will extract a bitter, milky substance that you can wipe off. Cut the remaining cucumber sections into three or four pieces each, and put them in the blender with the ice cubes, mint leaves and lime juice.

Blend, starting low until it’s a chunky slurry, then turn the blender up to high. If it’s too slushy for your taste, add water. A little bit of added yogurt works really well, too.

Sipping on this greenish milky treat is refreshing and satisfying on so many levels, and is a delightful way to pass the afternoon — while loading up on vitamins and fiber.

And here is a cool fact: These flavors go very well with gin.