This page is dedicated to low tech, guerrilla style home coffee roasting. You don't need expensive equipment; you don't need to buy your coffee from global brands (unless you want to). I've been roasting my own coffee for around 6 months now and home roasting is a lot less developed in the UK than in places like the USA. This page describes the whys and how. Not many people know that ‘fresh’ groun
d coffee is stale within 2 hours. When roasted and whole bean it will keep fresh for around 10 - 14 days. When green, the coffee bean stays fresh for a year or two. If you roast a batch of say 200g once a week (which in total takes 20 minutes and makes a little bit of a mess) you will always be drinking the freshest coffee. I didn't think there would be much difference but let me tell you, you will notice a massive difference. Second - you get to control exactly how dark you like the roast to be - you can experiment with pushing it further or less, much more than any manufacturer will do - so you get your coffee exactly the day you like it. Third - it’s a lot cheaper. I am drinking great quality really fresh coffee for around £1 per 100g. To buy good quality ground coffee you are paying more like £1.50 - £3.00 per 100g depending on the brand. So it sounds like a lot of effort but it really isn't. How do you do it? People ask me how to do it and I really want to encourage anyone to have a go - it sounds tricky but it’s really simple, so here’s how:
First of all – this process does create some smoke and heat and there is a risk of fire or accidentally burning yourself so do this at your own risk, use gloves and / or do it outside. I’m going to assume from here on that you are a sensible and competent adult and I don't need to point out the most obvious dangers…
So; get a wok or metal bowl and a hot air paint stripping gun and a wooden spoon. Put about 100g - 200g of coffee in the bowl and get the hot air gun in there, it also works if you put a little heat under it (very gently) from the stove at the same time. Have a stopwatch going as you do it. Just keep moving the beans around with the wooden spoon, never stopping, and keep moving the hot air around over the beans at a distance of a few inches. After about 2 minutes the beans will go from green to light tan colour and will start to give of a lot of chaff (its a messy smoky business so if you don't have a good extractor fan then see if you can do it outside), the beans will give off a smell like grass. Just keep going. Around 6 - 9 minutes (roughly; it depends on the ambient temperature, the strength of your heat gun, the quantity of beans) you should experience what is called 'First crack' - the beans start giving a loud cracking sound as the water inside starts to expand and will blow little bits of beans apart. Keep going. The beans will be beginning to go medium brown colour. Depending on the bean and how fast you are going the first crack will develop through the beans and finish in around 2 - 3 minutes. Then it will go quiet for between 30 seconds and 2 minutes (depends on the bean and how fast you are going) then around 9 - 11 minutes you will experience 'Second Crack'. This is another popping sound but more gentle - very much like the sound of rice crispies doing their thing (snap crackle and pop). The process seems to take ages to get going, but once its past first crack it can very rapidly go through second crack and on to burnt, so be careful. If you stop at the very beginnings of second crack its pretty much a medium roast, but if you like dark coffee keep going! Second crack can last between 30 seconds or 2 - 3 minutes. You will get a sense of a 'rolling second crack' where it feels and sounds like its well established. That should be around 11 - 12 minutes. You can even keep going still. If you really love darker coffee - what they call French roast or Italian roast - this is way past second crack and eventually you will see the oils come out of the beans and they will take on a very black glossy appearance. That should be at around 16 minutes or so (depends on the bean). When you have the beans as you want them, carefully put down the hot air gun and quickly dump the beans into a metal colander or sieve. The aim now is to cool them quickly so stir them in the colander, put them by an open window, if you have a cold air setting on a hair dryer you can try blowing that through the beans (I don't usually bother, just put them on the open window sill). And that’s you done! You should let the beans rest for a minimum of 12 hours to release their CO2 (called degassing). If you leave them two - three days though the beans flavour matures over time and gets deeper and richer. My thoughts on varieties
I always think of Columbian as like a good all rounder. Its super smooth, with just a hint of bite and it takes the dark roast well. It’s also got a climate for growing that is very consistent so Columbian coffees are always the same consistent good quality. Brazil is similar but with a little more bite. The majority of commercially available coffee comes from Brazil. The Central American coffees (in particular Guatemala) have more bite and acid sharpness. The African ones, Kenya and Ethiopia (Yirgacheffe and Harrar) are all well-rounded, medium suited coffees they work well in roasts that stop prior to second crack. I have also now roasted these to full city roast (into second crack) and they can take that too, the Yirgacheffe more than the Harrar. Kenyan coffee was good at a darker roast too. The African coffees are sometimes described as fruity or floral - though I'm not sure I can really taste that. The next major region is the Asian coffees - Sumatra Mandehling from Indonesia is really suited to dark roasting. Its very very smooth with almost no bite at all, so much so that I blend it with a little bit of something else just to have that coffee bitterness with the smoother darker tone of the Sumatran. Monsoon Malabar from India is similar but subtly different - again it suits a dark roast well. I'm just drinking a new Papua New Guinea one which is a bit like the Sumatra but not as full on. Again they suit darker roasts well and have smoothness and chocolatey flavours. So my recommendation would be to try a Columbian and to compare it to a Sumatra Mandehling. For more advice on home roasting and different aspects of coffee you can check out: https://www.sweetmarias.com/library/content/using-sight-determine-degree-roast If you navigate around the Sweet Marias site from there there are all sorts of interesting things about coffee and home roasting. http://www.sweetmarias.com/index.php
You can see that if you want to you can get pretty geeky about coffee! Here are some useful links to show how it’s actually done:
This is Tom from Sweet Marias talking about roasting colour changes – very informative
http://www.youtube.com/watch?v=aYy47C0Xw0I
This is probably the clearest demonstration I’ve seen:
http://www.youtube.com/watch?v=1TUnfvGPyV8
http://www.youtube.com/watch?v=KZHe4YwcdsE - another very clear demonstration
http://www.youtube.com/watch?v=boUmoMN4QXI - another clear demonstration with an interesting use of a second bowl and also spraying to cool. (Forgive him the soundtrack). When you start to delve into this you come across a variety of Heath Robinson type gadgets and home made contraptions. Here are a few in the category that I call:
Sweet set ups and strange contraptions:
http://www.youtube.com/watch?v=gg1g0v3r-h8 - Ben is clearly a pro
http://www.youtube.com/watch?v=gIO54NhGoTE&feature=related - doesn't look glamorous
http://www.youtube.com/watch?v=nstXcwdAvPo - heavy engineering
http://www.youtube.com/watch?v=me0sisv9FvI&feature=related - this one is so refined.. So enjoy your coffee roasting! Other useful links
http://www.homeroasters.org/index.htm
http://www.homeroaster.com/heatgun.html
Another really clear description:
http://swingleydev.com/misc/coffee_roasting.php
Taking it to another level – buying home roasting equipment
iRoast
http://greencoffeeltd.com/asp/roaster.asp
For the next step – a drum roaster
http://www.hasbean.co.uk/categories/Home-Coffee-Roasters/
UK Sources for green coffee
There are a lot of places to buy, just Google ‘green coffee’. These are the two places I go to, the first one is the one I use most. http://greencoffeeltd.com/asp/home.asp
http://www.thebeanshop.com/
