Acidity in Tea: pH Levels, Effects, and More
The word “acid” means something very different from what most people think. If you have ever tried to explain acidity to someone who does not understand it, they will probably think you are talking about salt or sugar. The term “acid” refers to a substance with a negative charge. When a positive charge (or potential) comes into contact with another substance, the two substances become positively charged. For example, when water touches ice, the two substances become negatively charged and move toward each other.
Water becomes less dense than ice because it loses some of its negative charge due to the movement.
When you drink tea, you are actually touching one of these substances called cations (positively charged atoms). The cation (positively charged atom) in the tea leaves is calcium carbonate. When you touch the tea leaves, you are making a small electrical current between them. This makes the calcium carbonate ions move toward each other and make up a positive ionic charge on each side of your mouth. These ions then stick together to form a film over your gums and tongue which is known as plaque.
The positive charge from the tea interacts with the negative charge in your mouth, which causes the bad breath.
How acidic or basic is your tea?
Most teas will have a neutral pH of around 5. This means that they are neither acidic nor basic. Many soft drinks have a lower pH than this, most of them around a 2 on the pH scale. For comparison, battery acid has a pH of 0 while bleach has a pH of 13. As you can see, the small effect that acidic drinks have on your teeth is nowhere near the damage that soft drinks and bleach do to them.
How does tea affect the body?
When the tea comes in contact with the water in your mouth, it has an immediate effect on your teeth enamel that coats the teeth. The most important layer of protection against decay and acid wear is the enamel surface. The enamel that coats the teeth is made up of mineral crystals that interlock like bricks to give the teeth strength and rigidity. When you drink tea, it has a negative charge which causes the enamel’s positive charge to be repelled. This repulsion makes the enamel separate from itself and weaken the structure of your teeth.
The main effects of drinking tea on your teeth are increasing decay and acid wear. These two problems are almost always caused by long-term drinking of beverages such as tea.A look at the decay and acid wear of the teeth shows how the tannins in tea cause an increase in both of these problems.
The way that tannins bind to the teeth is through a process known as adsorption. The tannic acid in the tea leaves binds onto the enamel of your teeth, which causes it to weaken and fall apart. Decay is a problem that occurs when saliva and other food or drink residues that stick to the teeth react with the bacteria in your mouth. This reaction leads to the formation of compounds that break down the enamel and eventually the dentine of the tooth. As decay eat away at your teeth, they can cause sensitive teeth and if left untreated, can lead to tooth loss.
Acid wear comes from your diet as well and has similar problems such as eating away at the enamel and causing sensitive teeth.
You may be thinking, can’t I just rinse my mouth out with water after drinking tea and not suffer these problems?
Unfortunately, the effects of tannins in tea have a residual effect. This means that it takes time for the effects to disappear completely after drinking tea. Even if you rinse your mouth out with water immediately after drinking tea, there will still be traces of the tannins left on your teeth.
Small amounts of tannins can be scraped off your teeth, but larger amounts of tannins can etch the enamel and even dentine. The damage doesn’t show up immediately after drinking tea, but if you drink it often enough and for a long enough time period, then the damage becomes permanent and requires professional repair.
As you can see, contrary to popular belief, drinking tea is bad for your teeth.
Sources & references used in this article:
Effect of pH on cream particle formation and solids extraction yield of black tea by Y Liang, Y Xu – Food Chemistry, 2001 – Elsevier
Effect of dolomite and biochar addition on N2O and CO2 emissions from acidic tea field soil by AZ Oo, S Sudo, H Akiyama, KT Win, A Shibata… – PLoS …, 2018 – journals.plos.org
Tooth surface pH during drinking of black tea by A Simpson, L Shaw, AJ Smith – British Dental Journal, 2001 – nature.com