Last weekend we (Fran, Jack and moi) represented Crankhouse at the Glasgow Coffee Festival. I met the founder, Lisa Lawson back in 2017 (or maybe even earlier) at a Roasters Guild Camp and I knew I had found a kindred coffee spirit. Someone who loved the industry and wanted to do something special. I remember Lisa telling me about how she started in coffee back in Sydney, being given a couple of hours 'training' before being let loose on a roaster whilst the owner was heading away. Turns out he was none other than Toby from Toby's Estate and that kickstarted Lisa's journey which led to her starting Dear Green Coffee Roasters back in 2011 and subsequently organised the first Glasgow Coffee Festival in 2014. Back then, the only festivals on the scene was the monolith London Coffee Festival and the then just started Manchester Coffee Fedtival. Lisa created something for the Scottish coffee scene and she and it have never looked back. Over the years Lisa has 'bugged' me (in the nicest way possible) to come up to GCF. I felt the time was right and I'm very glad we made the trip.
So, to my point. We decided to brew only filter coffees at the festival (we could have had an espresso machine etc but declined). I personally can only sip one or two espressos before my palate is blown. Filter is a different story. When done well, they can be delicate and vibrant and almost mouthwateringly refreshing. That was the goal, but our 'normal' roast style is as you all know 'omni', ie in the middle (in the safe zone). Developed enough that it can be brewed with any method, filter or espresso. Of course, we all know that this is a compromise. The light vibrant delicate compounds can be overwhelmed by sweetness and body through developing the 'brown' flavour components (melanoidins). Over the years I've toyed with the whole 'filter' versus 'espresso' argument related to roasting profile. Some excellent roasters differentiate their offerings into those distinct categories but I've struggled with the thought of the logistics, marketing and management of two very different profiles for the same coffee. In my mind it's a path that can lead to large amounts of waste. The 'omni' argument which I remember reading from Steve Leighton (ex HasBean) back in the day, says that a 'good' coffee can be roasted well and then brewed any way and it will taste 'good'. I absolutely did and still do concur... with a little niggling lower-case 'but' in the back of my mind.
The best filter coffees are those that have been roasted specifically for that brewing method. Ditto espresso. For GCF we wanted to represent two new coffees in absolutely the best way possible for filter brewing. The coffees we picked were both 'modern' Colombian coffees with significant interventions during post-harvest processing to create and enhance certain flavour characteristics. Not that it means much to anyone except a coffee roaster but our 'normal' style for single origins is to roast to approx 209/210C drop temperature anywhere between 9'30" and 10'30". That seems to work well for most batch sizes and most coffees. For the two GCF coffees we took a punt and roasted both coffees hard and fast. 8mins overall to 208C, keeping the energy intensity high through all the phases. ie light and fast. The key (in my mind) was to allow these coffees time to develop (or rest in the common vernacular). We roasted these coffees a full 3 weeks prior to the event.
We normally cup our test batches 24 hrs after roast and it gives us a reasonable picture of how close or far away we are from what we consider to be a decent profile for a particular coffee. After 24hrs, both these coffees were dry, astringent, grassy and just plain nasty. Trying to identify the favourable characteristics was near impossible and with our normal experiences we could have easily judged these batches as failures. But I had faith that these coffees would improve given enough time to 'rest'.
So, what happens during this resting period eh ? Well, I'm no scientist, but as some of you know I did complete the ZHAW Coffee Science Certificate and one of the lead instructors was Dr Samo Smrke (aka Dr Fresh). Samo studied the compounds that are developed during the roasting process and then how they change in intensity and composition over time after roasting depending on the conditions the beans are stored in. CO2 is perhaps the most well known and talked about by-product of roasting that is captured, but it is far from being alone. Numerous volatile (and therefore aromatic) compounds are created during roasting and some contribute significantly to what we consider to be the flavour components of coffee (we get 80% of our interpretation of flavour from aroma compounds).
Light roasted coffees have not had the time and temperature in the roaster to create enough pressure to fracture the cellular matrix as more developed (aka darker) coffees have. The micropores are more structurally intact and the volatile compounds created representing those light floral and fruit characteristics simply cannot escape and diffuse into the outside. Of course, you can roast super fast and hard and get high solubility which is the method used for capsules and instant coffee but typically this is done to maximise solubility at the expense of quality (using low quality coffees).
But, wait a week then that dry astringency starts to soften and there's a faint hint of those delicate fruit and floral notes. Another week, and less astringency still and more identifiable pleasant characteristics. Yet another week and BOOM.. there they are.. clean and bright and vibrant characteristics. That's exactly the experience we had for the two coffees we took to GCF, and clearly it worked since we had a queue of people telling us they'd heard these were two of the best coffees of the festival.
We were asked a few times if these coffees could be brewed as espresso. Of course they could since espresso is just another brewing technique BUT (definite upper case) you could simply not use your normal espresso brewing method and recipe. If you did, then the result would be something dry, thin, clawing and very very acidic without much body.
We had a few true filter proponents pleading with us to release these coffees as 'filter' specific profiles (just like GFC) and after some reflection I decided based on the old 'why not, what's the worst that can happen' principle to do just that. So, there we go, our first 'filter specific' roast profile coffees.
They come with disclaimers. Do not try brewing these coffees for at least three weeks after roast date. Do not try brewing these coffees on espresso unless you have the ability to change temperature, pressure, flow rate etc etc.
The two coffees are linked here.
https://www.crankhousecoffee.co.uk/products/edinson-argote-finca-quebraditas-sl-28
https://www.crankhousecoffee.co.uk/products/huver-castillo-finca-el-paseo-rocket-flower
They won't be around for long.
A little final word or two on why you can't take this approach with every coffee. That all comes down to the quality of the raw ingredient (green coffee) you're working with. Low density coffees grown in full or near full sun conditions with uncontrolled fermentation and drying simply will not have the flavour pre-cursors existing in the composition of the green coffee chemistry. A 'good' coffee that has been well processed might suit a faster lighter roast, but more typically we aim for more sweetness and red/darker fruit characteristics. Really good coffees that come from good varieties that are well processed with care and attention during every stage are the ones that have that potential to exhibit those delicate, vibrant characteristics.
That's part of the beauty of coffee.