The Flavor of Bottled Water

All water begins as two hydrogen molecules and one oxygen molecule. This is as far as the similarities go. Water is a universal solvent and dissolves just about anything that comes in contact with. As water that originates under the earth is in contact with minerals and trace elements in the geological strata it is gathering flavor along the way.

We would like to use the term Flavor to describe the complex integration of taste, smell and the tactile sensation food scientists call “mouthfeel”. This integration of sensation happens in the brain as a result of information relayed by sensors reporting taste, smell and tactile information. This integration is a very complex system and we are just at the beginning of understanding how it works. Lets look at the main components that that we integrate into flavor.

Taste
The oft-cited but misleading "tongue map" showing large regional differences in sensitivity across the human tongue is wrong. Taste cells lie within taste buds, which are located in various tongue papillae, hard and soft palate, and root of the tongue. A mistranslation of an early-1900s German thesis that was disproved in 1974 led to the confusion.  Unfortunately, it continues to be cited by glass manufacturers (Riedel) as a fundamental in their glass design. Taste buds are "skin-like" cells fairly evenly distributed on the tongue, with a life span of approximately seven days.

Smell
There are thousands of odors humans can perceive. An odor categorization scheme similar to the basic taste qualities has not been established yet. Odors are usually named according to the object they are associated with. (Smells like …) Olfactory receptors are true nerve cells that live approximately 30 days. The perception of odors can occur via the nose and the oral cavity while chewing.

Mouthfeel & Texture
The crispiness of a potato chip; the crunchiness of a pickle; the freshness of breads, cookies and crackers; the resiliency of a gum drop; the firmness of jams and preserves; the spreadability of butter, margarine and cheese; and the creaminess of puddings -- these are just a few examples of texture and mouthfeel characteristics that make food appealing and satisfying to consumers. Although it may be one of the most important properties, a food's mouthfeel is probably the least understood and most neglected by food writers. Carbonation or its absence together with the size amount and distribution of the bubbles are a significant contribution in the mouthfeel of water.

So when we talk about how something "tastes," we are really referring to its flavor - as an integrated sensation.

Many of us have grown up drinking chlorinated and fluoridated water from local municipalities. We have acquired a sense of what good water should taste like. We've all taken business and vacation trips to different countries and ordered water from a local restaurant only to be surprised by the taste. What we consider good water is an acquired taste and different waters sometimes taste strange. We are used to our water, it reminds us of home and it also shapes us*.

For example the mineral content of waters consumed in Europe and Australia has a much higher content of minerals (Total Dissolved Solids - TDS) then most waters consumed in the US. This of course sets expectation on how water should taste and what “good water” is. Most “taste” is local. With this in mind lets explore the flavor (taste + smell + mouthfeel) of water.

The taste differences in water are very subtle - especially when compared to wine – but are discernable. The subtle taste of water reflects its origin and terroir. Geological strata allow water to absorb different minerals which contributes to the unique characteristics of single source waters. Water without minerals is tasteless. Distilled water is tasteless and makes no significant contribution to your diet’s daily mineral needs. The addition of minerals in the water changes its characteristic and taste. Bottled water containing not less than 250 parts per million Total Dissolved Solids (TDS) may be labeled as mineral water. If the total dissolved solids (TDS) content of mineral water is below 500 parts per million (ppm), or it is greater than 1,500 ppm, the statement "low mineral content" or "high mineral content” is used to describe the water. Sea water. for example, has a TDS of around 34,000.

High levels of minerals in water (TDS) can sometimes produce the sense of a metallic flavor especially if not used to high mineral content waters. Presence and amount of minerals and trace elements determine the taste of water.

We usually do not associate a lot of taste with water.  By getting used to it we enjoy our water “tasteless” or neutral and do sometimes object to different tastes in other waters. Aside from this “acquired taste” phenomenon most will find the tastes listed below unpleasant in connection with water. This is more of a list on how water should not taste rather than how it should taste. Again, presence and amount of minerals and trace elements determine the taste of water.

Salty:

The hardness of water can have a significant influence on its taste. The hardness of water is measured in milligrams per liter (parts per million) and is mainly determined by its calcium and magnesium content. More magnesium and calcium make hard water.

Soft water                0 - 20 mg/l

Slightly hard                  20 - 60

Moderately hard            60 -120

Hard                             120 - 180

Very hard                  180 +

Sodium (sodium chloride or “salt”) is added to hard tap water to make it softer in order to not interfere with washing machines, dishwashers or bathing. Soft water reduces by half the amount of soap needed for cleaning and does not leave scum on your skin, cloth or dishes. A taste sometimes associated wit soft tap water or water with high sodium content is “saltiness”. There are many health benefits associated with hard water and its contribution to the daily mineral needs especially of magnesium. Soft water is designed for appliances not humans.

Bitter:
Sulfates are a combination of sulfur and oxygen and are a part of naturally occurring minerals in some soil and rock formations that contain groundwater. The mineral dissolves over time and is released into groundwater. Coffee, tea and other beverages made with water containing hydrogen sulfide may be discolored and the appearance and taste of cooked foods can be affected. Hydrogen sulfide produces an offensive "rotten egg" odor and taste in the water, especially when the water is heated.

Sour:
The pH scale ranges between 0 and 14. Water with a pH of 7 is neutral and less than 7 is acidic, a pH greater than 7 is alkaline. If the water has a pH of less than 4 the water may have a sour taste. Water with a pH greater than 8.5 has an unpleasant taste.

Plastic:
Inexpensive non PET plastic bottle especially if exposed to sunlight can cause an unpleasant “plastic” taste in water.

Rusty:
High level of iron can cause a rusty taste in water and give it a discoloration.

Water should not smell. If water for example contains hydrogen sulfide it can smell like “rotten eggs”.

This is probably the most overlooked aspect describing the flavor of water. We recently introduced the FineWaters Balance to categorize this overlooked aspect in describing the flavor of water. The FWB describes the “mouthfeel” of water based on the level of carbonization in five levels from still to effervescent, light, classic and bold. The FWB also establishes a narrow range of temperatures that suits each level best in the context of a fine dining experience.

Here is a quick sumary characterizing the taste of wine and water based on the Flavor= Taste + Smell + Mouthfeel matrix.

Taste:               complex

Smell:               complex

Mouthfeel:         uniform (with the exception of sparkling wine)

Taste:               very subtle

Smell:               absent

Mouthfeel:         complex

What does this mean? When tasting water the most important factor in its overall integrated sensation we call flavor is the mouthfeel generated by the size, amount and distribution of the bubbles or the absence of it.

The flavor of water is mainly determined by its mouthfeel and this should be the main concern when matching food with water or deciding on the perfect stemware. This is a very different approach to matching wine with food where the main factors are taste and smell and temperature is the only mouthfeel component.

To explore the water food pairing matrix based on mouthfeel see “Matching water and food in a fine dining experience”. The FineWaters Balance based on the mouthfeel factor has also a important consideration in choosing the right glass for enjoying fine water. Reed more about that in “What glass for what Water”

*The composition of the teeth reflects the water our ancestors where drinking in prehistoric times where there was little travel and no bottled water. In archeology it can be used to determine a persons origin based on comparing the mineral fingerprint of a water source with the fingerprint of the mineral composition of human teeth found at prehistoric sites.