Medium roast is often the Goldilocks of coffee. It keeps enough of the bean's origin character to stay interesting, but it doesn't push acidity to the level that light roasts do. For siphon brewing, that translates into a cup that's smooth, round, and approachable.

If you're just getting into siphon—or you're adding it to a collection without wanting to babysit every variable—medium roast gives you a safety net. You can be a little sloppy with water temperature or steep time and still end up with something drinkable. That's not something you can say about light roasts, which turn bitter and harsh when you push them too far.

Medium roasts also shine in other brew methods, so a bag you open for siphon won't be wasted if you're in a hurry and use a drip machine instead. That's a practical win for collectors who don't want a single-purpose bean.