"The roasting of espresso coffee is a skill as complex as blending but is often brought into disrepute by those roasters that approach this fine art as a study on the subject of cremation," says Matthew Algie's Technical & Quality Director, Ewan Reid

After that Ewan gets a bit technical. "Simplistically it's all to do with Roast Height - a function of time and temperature designed to alter the chemistry of the green bean and give the espresso the character we all know."

It is essential, apparently, that the roast should not be rushed as this can lead to a harsh and bitter tasting coffee, regardless of the temperature. Roasting has to be undertaken at a pedestrian pace, monitoring the final roast height of the beans with the utmost care as it is this which will determine the flavour of your espresso.

The final roast height will very much be determined by the origins that are being used and the type of market into which the beans will be sold. For instance, roast heights in Italy increase the further south you move, as does the blend composition with robusta being more prevalent in the southern regions. The problem with so much British-roasted coffee is that it receives a fast and light roast producing an astringent, sour and bitter tasting espresso.

"What we're aiming for at Matthew Algie is to move away from the conservative to produce different, unusual tasting coffees guaranteed to give you that 'out of body' experience which the finest espresso should" enthuses Ewan. "Tinderbox is one such product where we threw away the rule book. For this blend we use our unique Double roasting technique where we roast the coffee not once but twice." Double roasting? Wouldn't that make it burnt and bitter? "Not at all" he assures. "It alters the volatile acidity and lipid composition and what that means is that you get more of those exciting top flavour notes at the start of your espresso on the tip of your tongue followed by a syrupy mouth feel and body so full and flavoursome that it lingers for a seeming eternity." Quite!

This article originally appeared in Fresh 1