When looking for that morning jolt or to beat the afternoon slump, most of us will reach for coffee. But it turns out, not every cup has the same amount of that pick-me-up.

According to the experts, several factors determine how much caffeine will be extracted from the beans including the roast, grind size, brew time, temperature and style.

While you may believe a darker roast contains more of the drug since it tastes stronger, that’s not the case. “Blonde” roasts actually have more caffeine, notes doctors quoted by Readers Digest. In general, a brewed cup of Joe has around 95mg of caffeine.

Espresso works out to about 63mg on average and instant clocks in between 65 and 80mg.

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