Wet behind the ears — How and why water matters

The water understands | Civilization well;
It wets my foot, but prettily, | It chills my life, but wittily,
It is not disconcerted, | It is not broken-hearted:
Well used, it decketh joy, | Adorneth, doubleth joy:
Ill used, it will destroy, | In perfect time and measure
With a face of golden pleasure | Elegantly destroy.
- Emerson

Water is the most important food ingredient. When you buy food, most of what you’re buying is actually water. Water makes up more than half of your body weight. It’s what we look for on other planets. Water is everything.

For food scientists, water is critical to just about every food experience. Water affects how we perceive flavor and texture, how nutrient dense a food is, and how we preserve foods in the long and short term.

Fruits and vegetables are almost entirely made of water. Fresh meat and seafood can be 60–80% water too. Most foods we eat are at least half water. (Image: https://www.stayathomemum.com.au/my-lifestyle/ten-fun-ways-to-drink-water/2/)

Water is also very, very special. It’s a unique little molecule and its peculiarities define and affect a lot of our experiences in the kitchen.

The kink in a water molecule creates a ‘dipole moment’ which unevenly distributes charge across the molecule. This makes water molecules ‘polar’ and leads to a wide range of phenomenal from hydrogen bonding to the insolubility of non-polar substances like oil in water.
Carbon dioxide has two double bonded oxygen molecules on either side which don’t allow for any bending. The bond angle for CO2 is 180 degrees and all charges are shared evenly across the line. Because of this, CO2 is non-polar.

Chemically, water is pretty simple. One oxygen atom sandwiched between two hydrogens forming a very specific shape. A water molecule forms a 104.5 degree angle which leads to some important properties. This slight kink unbalances the electrical charges on a water molecule making it “polar” and leading to a whole range of phenomena (like the fact that oil and water won’t mix). This leads water molecules to orient themselves in different ways depending on where it is and what’s around it.

This little bit of electricity changes how water molecules interact with different substances. Like everything in the universe, water molecules try to minimize energy interactions — they shift and rotate to reduce the amount of energetic friction in the system. This accounts for a lot. It’s why salt will dissolve in water but oil won’t. It’s why oils will form a single layer on the top of a glass of water.

Free and bound water around dissolved salt. Sodium chloride breaks down into positively charged sodium and negatively charged chlorine ions in water. The ions’ strong charges make it easy for water to structure around it, binding those water molecules and requiring energy to remove them. Free water is far enough away from these ions and to pretend the whole thing isn’t happening and just ignore the exchange. (Image: http://academic.brooklyn.cuny.edu/biology/bio4fv/page/free_wr.htm)

When things get ‘wet’ water is attaching itself to molecules — forming different kinds of interactions depending on the material. It takes energy to break these bonds. The stronger the interaction between water and other components, the more energy is required to pull a molecule away for another purpose. When we talk about water in a system, we break it down into two parts: free and bound water. Bound water is water that is interacting with other components in the system while free water interacts only with other water molecules. Dissolving things in water ‘binds’ more of it, making it less available for things like bacterial growth. This is very important for food preservation as well as texture.

It would be odd to talk about water’s importance in chemistry but not mention its importance for life. Considering you’re about 60% water, the relevance should be obvious. Water is about more than just drink. Water is irrigation, sanitation, and locomotion. If we speculate that the wars of the future will be over water scarcity, then we ought to view today’s conservation as an act of preemptive peace (and surely there could be no greater peace than one which prevents war altogether).

Insect farming is incredibly resource efficient, especially compared to cattle. While it’s difficult to get exact numbers because farming varies so much around the world, it’s estimated that raising crickets can require as much as 2000 times less water than raising beef while delivering the same levels and quality of protein. (Image: http://4ento.com/2015/03/23/insect-farming-help-developing-countries/)

It takes a lot of water to raise livestock and this is one area where insects can deliver the most impressive benefit. Bugs can be raised on 2000 times fewer water resources than cattle because unlike mammals, birds, and fish, they often prefer to stay dry. They don’t require misting to stay cool in the summertime because they’re cold blooded and they don’t need gallons of water to hose down manure. Plants can require massive amounts of water too. California is the agricultural capital of the USA (it’s the largest dairy producer too), and the recent drought reminded us just how much water it takes to grow our food (not to mention maintain our golf courses and cemeteries).

Green and blue go hand in hand. Saving water saves lives.

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