''What's your recipe?''
If you think that cute barista with the horn-rimmed glasses and the featherweight moustache (or the glossy brown bob and the silky button-up blouse) is cute enough to talk to, those are the only five syllables you need to strike up a cordial, animated and probably lengthy conversation, because ''recipe'' in its everyday use describes perfectly the instructions for making a cup of coffee: ingredients, quantities, method.
To carry the conversation forward, or at least make sense of what follows, you'll need some more information.
First is the Specialty Coffee Association of America's Golden Ratio, which is the proportion of ground coffee to water for filter brewing: 60 grams of coffee per litre of water. So if your cute barista is brewing a single cup, the first item in the recipe will be 15 grams of freshly ground coffee - the standard dose for a 250ml serve.
With this in mind you'll know whether the barista is dosing up or down: if their recipe calls for 18 grams, you'll be able to nod sagely and say, ''So you're after bit more body and flavour?'' And if they say they're using only 12 grams, you can respond, ''Oh, pretty light, eh?''
The grind varies for different brew methods. French press needs the coarsest, while paper filter brews - pour-overs and AeroPress - need a medium grind.
The other ingredient is water, measured in grams because it's easier and more accurate to weigh water when you're pouring it from a kettle than it is to guess its volume, and because pouring it into a measuring vessel first would cause undesirable cooling.
Water temperature is important: somewhere between 93C and 97C, depending on the brew method; just off the boil is close enough for home use.
Then there's brew time: how long you leave the coffee and water in contact. The first part of the brew time is the bloom, when a little water - maybe two grams of water per gram of coffee - is added to the grounds to wet them and allow them to expand, before the rest of the water is added.
Brew time is somewhere between, say, 90 seconds for an AeroPress and five minutes for a plunger.
That should be enough to get you to barista conversation first base. Where it goes from there is up to you.
Coffee Supreme has bundled up a bunch of brew recipes into a handy booklet. See shop.coffeesupreme.com.au/products/brew-guide-by-coffee-supreme