Coffee, Tea...

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Peter Bryenton asked "I was wondering how much caffeine there is on average in an ordinary cup of instant coffee?"

Not an easy question as the consumer is in control of how strong they make the coffee and how big a cup they use.  Generally instant coffee powder is about 2-3% caffeine and instant coffee is about 330mg/L (about 75mg per cup).  But I know my first cup of coffee in the morning is considerably stronger than my last of the day.

Tea is generally only about 80% of the caffeine levels of coffee but, again, this varies with type, cup size and steeping time.  Herbal teas generally have none but be careful of flavoured green teas, they have similar levels to black tea.

Colas are about 100mg/L; a third that of tea and coffee.

The much vaunted 'Energy Drinks' are only permitted a maximum of 320 mg/L in Australia and so are on a par with tea and coffee.  Not that they would want an image of a little old lady sipping her cuppa to be equated to the macho image of the heroic energy drink urban warrior-rapper-sportsman.
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Done to a tea.

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Interesting story about tea recently:

A 44-year-old man presented in May, 2001, with muscle cramps. He had recently switched to drinking Earl Grey tea in preference to his regular black tea.

One week after the change, he noticed repeated muscle cramps for some seconds in his right foot. The longer he drank Earl Grey tea, the more intense the muscle cramps became. After 3 weeks, they also occurred in the left foot...

Earl Grey tea is composed of black tea and the essence of bergamot oil, an extract from the rind of bergamot orange (Citrus aurantium ssp bergamia), which has a pleasant, refreshing scent.

(You can skip this paragraph, if you wish) The adverse effects of bergamot oil in this patient are explained by the effect of bergapten as a largely selective axolemmal potassium channel blocker, reducing potassium permeability at the nodes of Ranvier in a time-dependent manner. This may lead to hyperexcitability of the axonal membrane and phasic alterations of potassium currents, causing fasciculations and muscle cramps.

In other words, it disrupts the way chemicals flow through the membrane of the nerve fibres, causing the neurons that connect to the muscles to malfunction.

I should add he was drinking four litres (a gallon, say) a day.

But it plays into my constant refrain: too much of anything is bad for you.

Food-wise, at least.
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