Black, oolong, white and green teas all come from the same plant, Camellia sinensis. The differences come from the harvest timing and processing, particularly the level of oxidation, a reaction that occurs when processed leaves are exposed to high oxygen levels. Black tea is fully oxidized, oolong is partially oxidized, while green and white teas are unoxidized. White teas are from early harvests, green from later.
Interestingly, the pH of water also impacts the extraction process. Low pH (acidic) water extracts bioactives better than high pH (basic) water. The pH of tap water is about seven, which is neutral, so there might be a benefit to adding lemon with your tea, rather than after its brewed.
Tea in the microwave?
The idea of making tea in the microwave is horrifying for purists. It’s argued microwaves are inferior to kettles for heating water, as there is less control over the temperature. But the microwave could actually be a useful tool for extracting more bioactives.
Microwaves can actually increase the levels of bioactives in your cup. Adding freshly boiled water to the teabag, steeping for 30 seconds, followed by a minute in the microwave (medium power) extracts more bioactives than a standard three minute steep.
But others have shown the same level of antioxidants reach the blood after consuming tea with and without milk. There’s no real science behind the age old question of when the milk should be added. The Royal Society of Chemistry suggests adding it first prevents denaturation, or clumping, of milk proteins, which might give the milk a stale taste.
Lower quality teas may also include more stems, which are higher in L-theanine than the leaves. So while fancy loose leaf might taste better, you probably get more bang for buck from a humble tea bag.
Health benefits might not be the only reason we choose to drink tea, but if you want to get the most out of your cup, patience is the key. Whichever type of tea you choose, the longer you brew, the more goodness in each cup.