Roast coffee at home with a popcorn popper

From thedomesticbarista.com

Roasting Coffee in a Popcorn Popper

You can easily roast coffee at home and home roasting coffee beans is very rewarding. The results are fantastic if you do it well and you are rewarded with a bold, clear, fresh taste that you just can’t get in most shops. All the different flavours are easy to pick out and the look and smell of the beans and the espresso are just incredible.

Before we begin, a warning… This is done entirely at your own risk. You are using a domestic appliance in a manner outwith it’s design and will void your warranty immediately. In addition you are dealing with high temperatures and combustable materials. Supervise the process at all times, be careful when handling hot items and don’t blame me if you burn your house down or hurt yourself.

You can buy home coffee roasters on the internet for anywhere between £150 and £400. Some of them are excellent, some are good and some are bad. You may well be interested in home roasting and this is a good way to try it out without needing a large outlay of cash.

The Popper.

The most important thing to look for in your popper is a unit that feeds in hot air from vents in the side of the popping chamber, as opposed to a grate in the bottom - this would be a major fire hazard. With this is mind, take a look around the high street and see what’s around. I settled for a ‘Rival’ popper, on sale for only £10 from Comet in the UK. Is this too good to be true - a coffee roaster for £10? Well, if you decide to give it a try and the results are phenomenal.

The Coffee.

You need raw green coffee beans to roast. Luckily there are a lot of places you can get these from. My favorite in the UK is Has Bean but there are many suppliers in the US too. I started with their Brazil Bourbon ‘Fazenda Cachoeira’, a good basic coffee with a smooth rounded taste carrying lots of caramel and almond flavours into the cup.

How To Roast.

Roasting with a popcorn maker is fairly simple. You just put in the beans, turn it on and wait the appropriate amount of time. Over the first few months of roasting I discovered some limitations of the popper and modified it accordingly.

The plastic lid that comes with the unit is completely unsuitable for it’s new role - it will melt! Throw it away!

The chamber doesn’t really hold enough beans on it’s own for a decent roast. More that a couple of scoops worth and they will be spat out around the kitchen wasting coffee and only allowing you to roast in small batches. The solution is to glue an extension made from a food tin to the top of the unit using epoxy resin. This enlarged the roasting chamber significantly so you can roast more and delivered chaff away from the unit.

The chaff is the biggest problem as it’s hard to fit a chaff collector that won't melt and it blows everywhere. Make a simple lid from a kitchen sieve. It’s not ideal but it does he job.

Weights and Volumes.

By weight, green beans to roasted beans should be weighed at a ratio of about 1.2:1, have this in mind when measuring green beans into the roasting chamber. A larger volume of green beans will result in a slightly longer roasting time and a richer, sweeter taste. Use enough beans so that they only just circulate when you turn the roaster on, this adds another 30 seconds to one minute to the roast time but the flavour is more complex and somewhat richer.

Green Bean roasting table:

GREEN BEANS	ROASTED BEANS	DOUBLE SHOTS (16g)
78g	64g	4
97g	80g	5
117g	96g	6

These amounts are a guideline, and work for my chosen espresso blend. Your mileage may vary depending on the size and variety of bean you roast but shouldn’t be too far off.

How long to roast for.

This varies entirely based on what taste you are after. There are two key phases in coffee roasting - known as the ‘cracks’. After about 2:30 mins of roasting you’ll hear the beans begin to crack, this is the beginning of the roast ‘propper’, then afterwards, at about 4-6 mins is the second crack, when small shards will come off the beans creating a crater apperance on some of the beans. When you choose to stop the roast is entirely up to you but i’d recommend just into the second crack. After 5 minutes you’ll have a good medium brown roast, and after 6:30 you’ll have a great, dark, shiny roast. And more than this and the beans will start to burn. I roast for between 6:00 and 6:30 and always get a great looking, smelling and tasting result.

Doing the roast.

Ventilate your work area, the smell is wonderful but if it fills the house it’ll soon settle on furniture and carpets causing them to stink. Then turn on the roaster for a few seconds to warm it up and pour in the green beans.

It’s wise to invest in a timer so that you can keep track of the progress of the roast. After a few attempts you should be able to start it and walk away, knowing almost exactly when the roast for a particular variety or blend will be finished. Stick around though - watch, listen and smell as the roast progresses. Watch as the sugars slowly caramalise, the water evaporates and the oils begin to cook. You’ll get a feel for the way things are going by sound (the ‘crack’) and smell soon enough but at first start checking the beans regularly after five minutes or so. Remove the filter if you’ve fitted on (it will be very HOT!) and peer into the roaster. If you have a metal measuring scoop you can simply lower this in a take a quick sample to judge the colour of the beans

Obviously, roasting is a personal preference and you’ll want to stop the process once you’ve got beans of a colour you like - so i’m not going to pontificate to much here. I like a bean to be dark brown and beginning to get a slight shine from the oils. That’s the taste I like and they’re very pretty to boot! Just experiment with a few batches and you’ll soon discover what you like, here are some of mine…

After roasting.

As soon as the beans are finished (you’ll have to keep peeking into the popper for the first few until you nail your timing) your priority is to cool them quickly so that they stop roasting. Put them into a sieve or a colander and take them outside, then stir them around with a wooden spoon getting the air flowing around them or pass them from one colander to another. After a minute or so they will have cooled to around room temperature. They you need to rest the beans for 1-2 days to let the excess C02 escape (called de-gassing). Put them into a tin with a loose fitting lid and keep away from strong flavors.

Some tips.

• Roast inside in the UK, it’s too cold outside in the winter.

• Roasting produces alot of aromatic smoke that smells terrible after a few hours, do it in a well ventilated kitchen and close the doors.

• Don’t roast more than you can use in a few days, remember thought that more coffee in the chamber (not too much, just enough to cover the air vents so that it only just circulates when first turned on) will give a slightly longer roasting time for a given colour and a more rounded, fuller taste.

• Have the vacuum cleaner handy for dealing with the chaff before it gets everywhere.

• Once again, this is done entirely at your own risk. You are using a domestic appliance in a manner outwith it’s design and will void your warranty immediately. In addition you are dealing with high temperatures and combustable materials. Supervise the process at all times, be careful when handling hot items and don’t blame me if you burn your house down.