I like to think of “bathtub gin” as “Martinis by the pool,” but that’s not where the expression originated. It came about during Prohibition when people would “make” their own gin by adding mail-order juniper flavoring to low-quality alcohol to help mask its awfulness. The weird thing is, gin cocktails were awfully popular back then.

Today it is still legal to make gin this way- not in the bathtub, but by adding juniper oil and other flavors to a neutral spirit like vodka. Thankfully, most of the gins with which we’re familiar don’t do it like that. Gin usually starts with high-proof neutral spirit made from grains like corn, wheat, and rye. The gin distiller then selects a range of botanicals or botanical oils to infuse into the spirit, then redistills everything together.

There are many different distilling methods gin makers employ, but this is probably only interesting to folks like me who spend our spare time hanging out in distilleries on vacation. More interesting are the types of botanicals that go in to gin. Traditional brands like Beefeater, Plymouth, and Tanqueray contain many ingredients like citrus peels, coriander, cinnamon, and cassia bark. Newer gins on the market like Bombay Sapphire, Hendrick’s, and Martin Miller’s also include things like lavender, ginseng, rose, and green tea. All gins, by definition, must contain juniper (berries that smell like pine trees) as a dominant flavor, but the newer ones tend to put less of it in.

While vodka lovers and gin lovers are usually different sorts of people (though I find versatility provides more options in the bedroom and the liquor cabinet), when it comes right down to it gin is really just juniper-flavored vodka. If you’ve got vodka drinkers over for cocktails and you only have gin left, just tell them their drinks are made with “botanical vodka.” If you’re in the opposite situation, tell them the vodka is “diet gin.” Lying to your guests is the most entertaining part of entertaining them.

The combination and concentration of the juniper, spices, citrus, and other botanicals is what gives each gin its unique flavor and makes it a better or worse fit for different cocktails. Some modern gins are so very citrusy and floral that they can be too perfumey for a Martini. (Hey, this drink smells like grandma!) On the other hand, when you add an intensely juniper-heavy gin to a Gimlet or other mild cocktails, sometimes all you taste is the juniper. (Hey, this drink smells like where grandma is buried!)

The trick is finding the right fit for each gin for your mouth. I prefer the old-style gins in a Martini, Aviation, Pink Gin, and Negroni. With the more-floral, less-juniper gins I like the Salty Dog, Gimlet, White Lady, and Vesper.

But I find that no matter what kind of gin you have in the house you can always add it to tonic water and it will taste just fine. Tonic is the mixer that swings both ways.

Camper English is a cocktails and spirits writer and publisher of Alcademics.com.