#10 Why Omniroast?

Often in Australia you will see “Espresso Roast” or “Filter Roast” printed on roasted coffee bags available to purchase at most cafes. What do these mean and more importantly, are they useful at all?

I made the distinction of being in Australia because when I was in the USA I did not see any labelling based on brewer specific roasts. By brewer specific I mean bags of coffee labelled with “Espresso Roast”. This is aimed at helping the consumer make an informed choice of coffee beans to be used in an espresso machine. Likewise, the bags can be labelled with “Filter Roast”, this is typically in reference to filter brewing; a brewing process where hot water is poured over coarsely ground coffee and filtered through a paper filter. When I travelled through the UK and Norway, I didn’t see any brewer specific coffee labelling, the coffee would just come in a bag with tasting notes*.

Why do Australians feel the need to describe the coffee as suitable for espresso?  And why is espresso different to filter? Is the distinction based on the way coffee is made or the way Australians perceive drinking coffee? Can some coffees be brewed on any device? I believe the answer to the last question is yes! Some coffees can be brewed on any coffee brewing device you want, if certain food manufacturing processes are adhered to in the roasting of the beans. Coffees that are roasted with the intention of being used in this way are referred to as Omni-roasted.

My Micro-roastery: Blue Sky Coffee, roasts everything as an Omni roast. We cup** the coffee and decide based on the flavours presented how best to modulate the roast favourably to bring out the flavours we feel the coffee displays best. From my perspective the coffee is then “finished”. That is to say it has balance between acidity, sweetness and bitterness and accurately reflects the beans growing conditions and primary terroir flavours.

For many roasters, however, there seems to be a degree of separation between espresso coffee and filter coffee. With filter being generally considered to need a lighter roast degree. Conceding that espresso is quite unlike other brew methods in that it extracts coffee under pressure, I still believe that a coffee’s tonality and flavour owing to its terroir should be prioritised, a consistent extraction - espresso or otherwise - should still be able to highlight these flavours. Why the need for different roast profiles?

“Accepting that the defect is more noticeable in espresso, roasting espresso darker to avoid grassiness is not pursing excellent espresso; it’s the practice of accepting subpar filter.”

Typically, an answer I’ve heard is that filter roasts - or lighter roasted beans primarily used in filter - taste grassy. Grassiness, as its name suggests, gives the beans a freshly cut grass or vegetal flavour. It’s caused when not enough of the raw coffee has been broken down by the milliard*** reaction in a roast. It tastes like grass because it literally has too much raw carbohydrate (or fibrous plant matter).  If this defect occurs the coffee needs to be roasted darker, it will be apparent regardless of brew method used. As such, it is not a sufficient justification for brew specific roasts. Accepting that the defect is more noticeable in espresso, roasting espresso darker to avoid grassiness is not pursing excellent espresso; it’s the practice of accepting subpar filter.

Here is where we see another aspect to my roast philosophy at Blue Sky, while I am roasting light to highlight the coffee’s core flavours, I have not made the assumption that grassiness and vegetal tonalities are inherently part of the coffee, they are not. Understanding roast derived flavours in the grey areas of too light or too dark is crucial. It allows me to separate and identify what the roasted vs inherent flavours are and chose where and how to amplify them.

If grassy flavours exist at the one end of the spectrum, roasty flavours exist at the other. A coffee that has been roasted dark will lose almost all sucrose (sugar), even the by-products of sugar browning (creation of secondary sugars through caramelisation) will eventually dissipate and yield only burnt carbonised material.

To further confuse matters there is a technical reason for roasting darker, the coffee becomes more soluble in water. The beans have less organic matter (because it was incinerated) and therefore will be more porous and breakable at the hands of a grinder. For the average “pro-sumer” running a modest espresso setup at home this will be a welcome relief. Grinders aimed at the home market generally show a poor level of grind quality with a wide distribution of particle sizes. Put simply this means shots will run faster if they have less soluble coffee. Such as in light roasts. So, it’s a bit less hassle for your grinder if the coffee is easier to get to “run right” and get a comfortable thirty second shot straight out of the bag.

While I’m not against making coffee easier to brew for everyone. I feel like we need to go back to flavour and ask ourselves what kind of drinking experience we want to achieve. I myself want the wine tour, I want terroir, growing characteristics, characters that directly harken back to the farmers fermentation technique, plant husbandry, cultivar choices. I get goosebumps when I taste a coffee that’s sweet and clean with high quality flavours, because I know I am drinking a piece of art, produced by a master of their craft. Isn’t this the end goal for all foodies? Total transparency between farm and cup.

Granted most espresso roasts do not take it this far, but it’s important to remember that raw coffee only has 6%-9% total sucrose, the lightest of light roast (which probably have grassy tonalities) only have a maximum of 1.17% sucrose****. There is only one way but down from here, less sugar means less sweetness. We have so little to play with here we cannot afford to destroy any of our coffee’s best ingredients just so that it is more soluble on an espresso machine. When I create an Omni roast I try and aim to make it workable. But ultimately if a coffee is developed enough to not exhibit grassiness, it is soluble and should be able to pull a shot of espresso, albeit at a finer grind setting that a darker roast.

In many of the coffee I’ve seen given the treatment of an espresso roast there is little of the origin coffee in the roast profiles, and while such a roast will undoubtedly have a manageable level of acidity, we have lost so much of that coffees individual character I feel this trade off isn’t worth it.

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The Author Gratefully acknowledges the generous help of Cooper Ahrens with ghost-writing this piece

*Tasting Notes: descriptive notes used to describe the coffee to a consumer prior to tasting it. Usually using commonly tasted flavours: fruits, chocolates and sweets etc.   

**Cupping: a coffee evaluation test involving brewing a measured amount of coffee grinds in a hot water bowl. The result is a coffee soup we taste on spoons as soon as the bowl is cool enough to drink from.

***Maillard: a sugar browning reaction that occurs in organic matter when it is subjected to heat. I.e Roasted.

****Citation: Trugo, L.C, Marcie, R 1985 “The use of the mass detector for sugar analysis in coffee products”, Proceedings of the 11th ASIC Colloquium. Cited in: Rao, S 2014, ”The Coffee Roaster’s Companion”, 2014, p. 17. NB. Rao also notes here the degradation of sugar in darker roasts also reduces sugar but as the sucrose undergoes caramelization it creates acetic acid, further decreasing the level of sweetness.