"A mathematician is a machine for turning coffee into theorems."
(Rényi actually said "device", not "machine", but this little saying of his has become part of the folk-wisdom of mathematics, and like many sayings, it has various forms; the version above is the version I "grew up" with, mathematically speaking).
I started drinking coffee the summer I was working on my doctoral dissertation. My thesis advisor had gone to Oxford for a whole year, and I scraped together money to follow him there for just one summer. "Summer" is a relative term in Oxford, especially in June, when it rained every day but one. The heat in the buildings was off (because, y'know, "summer"), but the outside June temperatures never rose above 60-some degrees. I was miserably cold a lot of the time, and I turned to warm drinks to try to help me feel better. British tea was an acquired taste that I couldn't manage to acquire, so I took up coffee.
Fortunately for me, July and August warmed up (AND I figured out the Sobolev inequality that helped me nail that compactness argument that I needed to finish my thesis--whoop!), but the rainy, cold June had made its mark on me: by the time I left Old England to return to New England I was hooked both on mathematical theorem proving and on coffee.
Coffee, coffee, coffee . . . I love it. There are so many ways it has permeated my life. Like Bach, I have sung (or rather, said) its praises: in our family game of "I like", my third or fourth offering has often been, "I like . . . drinking coffee."
I've designed my bags so that they can carry my favorite insulated bottle (perfect for getting coffee on the go).
And I have come to love the coffee-making ritual in our marriage: my husband grinds the coffee beans at night, and I press the "start" button in the morning. I make coffee and transfer it to a thermos for low-cost warmth preservation.
Coffee has been a part of my mathematical identity; it's been a part of my marriage; it's shaped the physical possessions that I own and the way I model gratitude with my children.
Can you sense there's a change coming?
There have been downsides to drinking coffee. The expense . . . well, since we mostly brew coffee at home, coffee has been an affordable luxury, even to a Miser like me. Even so, there's no getting around the fact that coffee is one of the more expensive ongoing pantry purchases we make in our home. A larger downside is that I've been so addicted for so long, that even when I don't *want* to shape my life around coffee, I sort of *have* to. In particular, when I'm traveling, locating early morning coffee (trash-free, where possible) has loomed large in my travel arrangements.
I've toyed around with the idea of giving up coffee for a while. I held back in part because it would be just another way to freak out my husband, who already thinks I live a life of hair-shirt-self-sacrifice, and worries about being dragged into the same. But then I came down with a health scare that turned out to be persistent heart burn (it's how I learned I'm beautiful on the inside). And after taking mondo piles of medication day after day, I finally decided to say good-bye to . . . well, to a big part of my life.
And so I've gone over to the herbal tea side of the world. (Note: herbal teas -- cheaper than coffee and not addictive). I get them from market (canning jars, no trash). And just so I can inject a little of the happy side of me in here, I'll note that canning jar lids make great mug covers to keep the tea warm, and small canning jars are a great place to drop your tea ball when you take it out of the mug.