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I once daydreamed of building a machine that could roast, grind, and brew coffee, all in one. After becoming a home hobbyist roaster almost three years ago, I gave up on the dream machine when I realized that even if I somehow pulled it off, in practice, it would actually kinda suck.

Well, Bonaverde actually built it and wants your money on Kickstarter, and everyone has asked me about this today. It’s been widely reported by the coffee-gear-obsessed tech and gadget press, but I have some concerns.

A lot of their messaging is about coffee farmers with progressive-sounding music, but they’re conflating very different things: bean sourcing, unroasted bean distribution, freshly roasted coffee, home roasting in particular, and using one integrated machine to do roasting and brewing. The machine is the new part. The rest of it is a nice story, but unroasted (“green”) bean sourcing and home roasting have been easily available for years.

Conceptually, there are a number of potential problems with an all-in-one machine:

• Smoke: Roasting coffee produces a lot of smoke — so much that I roast under a window with a full-sized box fan in it, blowing out. Bonaverde claims that their air filter prevents the smoke from getting out. We’ll have to see how well this holds up in practice, but I’m skeptical — I’ve never seen a coffee roaster that emitted so little smoke that you could keep it on your kitchen counter normally.
• Chaff and oil: Roasting coffee is messy. Not only does chaff get everywhere and into everything, but the inner surfaces of the roaster can get covered in a sticky, grease-like film. The cooler the surface during roasting, the more the oils accumulate into a sticky film rather than burning off.¹ (That smoke-filtering exhaust system might be problematic for this.) Chaff and oil buildup can shorten the lifespan of home roasters (or even become a fire risk) and requires frequent cleaning, often with some disassembly to reach it all. The simpler the machine, the easier it is to clean, and the longer it’s likely to last. I’d be wary of the Bonaverde’s longevity in this regard since it’s so complex, small, and integrated.
• Taste: Common roaster wisdom is that coffee actually tastes best one or two days after it’s been roasted. Bonaverde’s FAQ mentions this but basically says they don’t believe it. Anecdotally, in my roasts, I think it does taste better the day after. I’m also concerned about the roasting profile — a full roast in only 4 minutes is very fast. Slower roasts can actually taste better as the flavors develop differently and more evenly.
• Manual stopping: Roasts pass through “too light”, “perfect”, and “burnt” very quickly — in a 15-minute roast, this entire progression might take only the last 2 minutes. (And the interval between perfect and burnt can be the last 15–30 seconds.) Different beans roast at different speeds, too, so this week’s batch will probably need more or less time than last week’s. Doing it right requires a human to look, listen, and decide when to stop the roast. Air thermometers in the roasting chamber aren’t fast or accurate enough to do this automatically and achieve consistent results, especially at the rapid pace of a 4-minute roast. (I don’t think we even know if the Bonaverde machine uses a thermometer or just a fixed-time program.)

To be fair, all of that is speculation — the Bonaverde machine may blow all of those concerns out of the water. Time will tell.

But the biggest problem is the inflexibility of having these three very distinct roles — roasting, grinding, and brewing — locked into one integrated machine.

Want to roast a pound of coffee to take to your parents’ house for Thanksgiving or give as a gift? Too bad. Want to use a different grinder? You can’t. Want to brew with an AeroPress? At best, you’ll need to stop it halfway through and pull out the grounds, which is inelegant and error-prone. How about a French press? Nope, the grind size is too small. Serving a lot of coffee at once for, say, a dinner party? You’ll have to wait for an entire roast between each pot, not just brewing.

And when one part breaks, or you’d like to upgrade just one role, you’re out of luck.

Freshly roasted coffee is awesome, but I don’t think this is the way to do it. For the same price, you can get a standalone Behmor home roaster today. Sure, you’ll need to buy a grinder and brewer separately, but you probably already have those if you’re considering this machine, and the separate components will be far more versatile in practice.