Coffee Roasting for Fun

roasted beans

I like espresso coffee.

Espresso coffee is best made from very recently ground beans, that were fairly recently roasted. Ground seconds before from beans roasted within the previous 3 days seems best.

To achieve this, you obviously need to grind your own beans. There are a number of people that will roast-to-order and post beans to you, so you get them within a couple of days of roasting. My favourite (from which I've had truly excellent service and coffee) is Has Bean.

However, an alternative is to buy green, unroasted, beans and roast them yourself (Has Bean will sell you the beans green as well as roasted). This page is about doing just that, or rather, using that as an excuse to play with microcontrollers.

Home Roasting

There's lots of stuff on the internet about coffee, and quite a bit about roasting your own, probably because geeks like coffee, and whatever geeks like is found in abundance on the internet. Probably the classic reference is Sweet Maria's. They are in the USA, and I've never purchased anything (or even corresponded with them), but it's a good jumping off point for more information. Go and look at that for a more balanced overview.

The most widely favoured technique seems to be the use of a hot air popcorn popper machine (though there's a certain raw elegance to the dogbowl & blowtorch approach). Alternative approaches use various frankenstein marriages of household appliances: bread-maker machine plus hot air gun (that one's particularly popular in Australia, it seems), convection roasters plus stirring popcorn machine are common. For large capacity, modification to gas-fired barbecues seems popular.

I first of all adopted a popcorn popper approach, and vastly overcomplicated it with microprocessor control. The popper made a mark 1 and mark 2 roaster.

Eventually, the popper roaster expired. The motor stopped running (and when I dismantled it, the plastic chamber base was quite badly cracked - I think poppers are not designed for the heat and duration they are subject to when roasting coffee). Also, it only ever did very small batches. Consequently, I'm now in the process of building a rotisserie oven plus convection roaster based approach, and will naturally over-complicate that. This will be mark 3.

DISCLAIMER

IMPORTANT - from here on, I strongly advise you do not do what I describe. You will probably electrocute yourself, you family, pets, friends and neighbours. Things will melt. Things will burst into flame. You might bring civilisation to its knees. Of course, if this is the sort of thing you get up to on your own, without encouragement, you might find this useful or interesting. Presumably, you're also competent enough to do it (since otherwise they'd already have buried you). I don't endorse anything I describe here as being safe.

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