The SCAE Gold Cup Research programme, which I have discussed previously, is a timely piece of work, but also a massive pain in the arse. I applaud the SCAE for undertaking this endeavour, as it is an ungainly, painful operation to run. It has been conducted 4 or 5 times at various locations around Europe now, I’ve been involved with 2 of those, and it’s no easy task. You have limited time to dial in, sometimes with unfamiliar equipment. Not to mention the difficulty in deciding on one coffee which should represent all coffee.
The scope of the research is to determine taste preference across 5 different levels of extraction, with strength being constant. That in itself would be good to know. However, it isn’t designed to cover the entire landscape of coffee brewing. It would be utterly impractical to do so, given the limitations of resources and time afforded to the study.
What if there was an easier way?
This kind of study needs several things, first off data, lots of it. The more data acquired the more powerful the results. It needs sensory evaluation of coffee made to a known recipe and of a known strength (extraction can thus be inferred).
There are thousands of users of VST refractometers around the world. Most probably brew coffee everyday. If each of these users submitted only one measurement to this study we would have a significant, useable sample size. If some of these users submitted multiple measurements over the course of a few months, we could have a huge, powerful sample size.
So, here’s what I am proposing. Anybody with a refractometer can (and should) submit data to this study.
Using a simple form, submit the recipe, the TDS/strength, and a score (your evaluation of the brew).
This approach has its pros and cons.
- It gets around the need to pick one coffee. Now it is every coffee or any coffee.
- It potentially allows for a much wider coverage of the brewing chart.
- It could allow for a large number of samples to be acquired in a short amount of time, with minimal effort.
- There will be inherent variability between users, in how they brew, and how they measure, and how they score. There will inevitably be some bad data. However, given a large enough sample size you would hope this would even out.
I would envisage this running for about 6 months, at which time the data would be published and freely available for anyone to use/analyse.
The following is the suggested protocol (I thank Vince Fedele for his help on this).
- Measure (by weight) and record your ground coffee and your brew water.
- Transfer a small sample (4-5g) from the brewed (& filtered) coffee to a cool glass/cup.
- Draw sample into pipette/syringe, expelling as much air as possible, leaving the tip submerged in remaining sample. Do not measure at this time.
- Evaluate coffee over your normal range of drinking temperatures, choose score based on scale below.
- Remove pipette, discard a few drops, then transfer to sample well and measure as normal.
If anyone has thoughts on improving this experimental design please leave a comment below. The basic intention of the steps here is to allow the participant to taste the coffee without being influenced by the measurement. Therefore it is key to try to prevent erroneous readings due to evaporation over time.
I suggest iPhone users follow this guide to add a shotcut to their homescreen for frequent use.
The scale used for evaluation is a 9 point hedonic scale similar to this: