Wednesday, September 15, 2010

Sticky Honey

At first honey flows as a thick glop that evolves into an seemingly infinite stream. I never bother to wait long enough for it all to come off my measuring spoon, instead I just lick it – actually I could just lick spoons of honey without putting it into anything (like everyone else, I'm hardwired to like sweet things). Honey is sweet in a complex way I find intriguing. I'm always on the lookout for different types of honey to try. Recently, I bought a big plastic tub of clover honey on my trip east. Years ago, while wandering around downtown Munich, I found an entire shop devoted to different types of honey – I was amazed by the sheer number of types of honey: lavender, clover, buckwheat, avocado, heather and the list could go on. I think people really like honey.

Honey has been consumed since ancient times, likely as far back as 10,000 years ago or more. At one time honey was often the only sweetener available. When the tomb of King Tutankhamun was found in 1922, a pot of honey was discovered inside that was still edible (I'm not sure I'd go for potentially cursed mummy honey). On top of sweetening, honey has been used medicinally for eons. Modern studies have shown that honey helps healing wounds, it even provides a soothing effect when applied to burns. It also is a possible treatment for gingivitis, cataracts, ulcers and more.

According to 'The Flavor Bible', honey is a moderately loud flavor considered 'rustic' that goes with both the savory and the sweet. Every honey made tastes unique because the flavour of honey is determined by the flower the nectar came from, and there are almost an infinite number of possible flower combinations. Bees can be picky about what flowers they use. In one study, beehives were situated in the middle of avocado orchards while the avocado trees were blooming. Avocados produce a lot of nectar, so it should have been a win-win for the trees and bees. It turned out the bees preferred nectar from flowers surrounding the orchard.

Once nectar is brought back to the hive, the bees ingest and regurgitate the nectar multiple times until it is partially digested. At this point, it's stored in the honey comb while worker bees fan it with their wings until enough water evaporates. When the water content is low enough, honey will never spoil. When finished, honey has the following composition: 17.1% water, 82.4% total carbohydrate and 0.5% proteins, amino acids, vitamins and minerals.

At 64 calories per tablespoon, honey is a good source of nutrition. Honey colour is an indication of how strong the honey will taste. Light honeys are mild and dark honeys are stronger. It turns out that the darker honeys often have more antioxidants and potassium, but beware, honey can darken during shipping and storage.

What I think is cool about honey (beyond snacking possibilities) is that it's a non-Newtonian fluid. A non-Newtonian fluid is a fancy way to say that it doesn't respond evenly when poured in contrast to a Newtonian fluid like water. If you take a spoon of water and turn it over the water will flow out at an even rate. If you take a spoon of honey and turn it over, at first it will just bulge then a thick stream will slowly descend downwards. Over time the stream will speed up and thin.

In a non-Newtonian fluid the relationship between shear stress (pushing parallel to flow) and strain rate (how fast it deforms) is non-linear. That is, a simple number, usually viscosity (resistance or thickness of the fluid), can't be used to relate shear stress and strain rate together. To add complexity, this effect can even vary with time. The large molecules of the honey form links with each other that have an elasticity to them and can actually counteract for a while forces like gravity. Eventually, the flow overcomes this resistance and links will break. Other links will form and this non-linear effect will persist.

I'm going to keep looking for different types of honey when I travel and I won't expect it to come out of the jar easily.

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