Tea Chemistry - Periodic Table of Videos

TL;DR

Adding lemon to tea causes a color change due to chemical reactions, and different teas have varying chemical components.

Transcript

well in a couple of days time it's the Chinese New Year and we thought we could mark the Chinese New Year by looking at a bit of the chemistry of tea so before we start have to make some tea I will just go along the corridor to the start and Robin so we're going to make some green tea and some ordinary tea as well so we can compare them I don't rea... Read More

Key Insights

• 🍵 Green tea and ordinary tea come from the same plant but are processed differently.
• 😂 Lemon juice causes a color change in tea due to chemical reactions with indicators in the tea.
• 😂 Different types of teas have varying chemical components, influenced by environmental conditions and processing methods.
• 😂 The acidity of lemon juice affects the color of tea due to its impact on the molecular bonds.
• 🥹 Tea decaffeination using compressed carbon dioxide is a safer and more efficient method compared to older techniques.
• 😂 The chemical analysis of tea involves using nuclear magnetic resonance spectrometry to identify various components.
• 🍵 Dark tea contains more caffeine than green tea, as processing and fermentation concentrate the caffeine content.

Questions & Answers

Q: Why does adding lemon juice to tea cause a color change?

Lemon juice is acidic, and tea contains molecules that behave like indicators. The acid from the lemon juice causes a chemical reaction, changing the way the molecules in the tea absorb light and resulting in a lighter color.

Q: Does the order of adding milk in tea make a difference?

Some people believe that adding milk before or after the tea affects the taste, but chemically, there is no significant difference. Personal preference plays a role in this debate.

Q: How do different types of teas vary chemically?

Different types of teas have varying chemical components. Factors like sunlight, rainfall, and processing methods influence the amounts and types of chemicals extracted from the tea plant during brewing.

Q: How is caffeine removed from tea and coffee for decaffeination?

Traditionally, dry cleaning fluid was used for decaffeination, but nowadays, compressed carbon dioxide (CO2) is preferred. Supercritical CO2 can dissolve caffeine without leaving residue, making it a healthier option. The extracted caffeine can be sold to make caffeinated drinks.

Summary & Key Takeaways

• Green tea and ordinary tea are made from the same plant but processed differently.

• Lemon juice, being acidic, causes a color change in tea due to the presence of molecules that behave like indicators.

• The different types of teas have varying chemical components, influenced by factors such as sunlight and rainfall during the growth of the tea plant.