Our roasters: The reason our coffee tastes great - Part two

We love roasting our coffee beans to perfection - and it’s an art we take seriously. In the second of our series of blog posts on coffee roasters we use, we’re going to look at the STA Impianti Drum Roaster.

WHAT IS DRUM ROASTING?

Drum roasting is predominantly a conduction method, where beans rotate in a heated drum that’s rather like a cross between an oven and a tumble dryer. Coffee roasters tend to fall into one of two camps - either the drum roasting aficionados or those that prefer ‘fluid bed’ roasting.

AND FLUID BED ROASTING IS...?

This method is predominantly a convection method, where beans are circulated in hot air, rather like popcorn.

THE YCE WAY

At York Coffee Emporium we’ve found that each method has its own merits. Coffee roasted in the fluid bed roaster has a cleaner and brighter flavour with good acidity. Coffee roasted in the drum roaster tends to have a deeper fuller body with complex character. We tend to roast our South American and Central American coffees in the fluid bed and our Africans and Javas in the drum roaster.

ONTO THE STA IMPIANTI DRUM ROASTER

This machine was produced in Italy in the early 70s and so it’s purely manual with no clever computer programmes to help. It’s just the machine, the roaster, stopwatch and temperature gauge. It roasts five kilos at a time, is powered by electric motors and heated with natural gas.

We got the machine from a place in Croatia, who no longer required it. We had to make our own chaff cyclone (this collects the dry husk-like skin of the bean while roasting), which we crafted out of various mechanical parts. A little rough and ready but it works a treat!

You need to know what you’re doing when you roast coffee on a quirky piece of machinery like this. With some of the more challenging beans, such as Monsoon Malabar, you have just a ten second window in which to deliver great coffee or you’re left with a burned mess! It’s a fantastic thing to operate. As coffee beans are organic, every sack is slightly different and we have to know how to manipulate the roast profile each time. With a bit of trial and error you can make sure that each coffee has the best roast profile possible.

We’ve modified the machine a little by incorporating a modern digital thermometer, a modern digital stopwatch and made some adjustments to the gas flow and airflow to ensure the correct flame and heat for each coffee roasted. Other than these tiny adjustments, it’s essentially the same machine as it was when it was first produced forty-odd years ago. It’s a really cute machine and a firm favourite with us.

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