Sages and philosophers from various world traditions have counseled “Everything in moderation,” and, stated another way, “Nothing in excess.” These aphorisms apply to caffeine, too, because too much of this otherwise beneficial chemical can cause insomnia, nervousness, muscle tremors and stomach upset.
When people talk about having “a cup of coffee,” they don’t necessarily mean 8 ounces (236 milliliters). For example, many people go for the large size of coffee at McDonald’s restaurants and Starbucks, at 20 ounces (591 milliliters). Or at home, they may have a 12- to 16-ounce mug.
So when you read guides online that say an 8-ounce cup of drip java has about 163 mg of caffeine, you can more than double the amount of the stimulating chemical for a 20-ounce size. Drip coffee is the kind that drips through a filter to produce that cup or mug of the elixir that so many people say they can’t start their day without.