Prufrocker: The Blog

Staff Mail-Around Mayday

Just a note on the modified espresso recipe... also note the new clump crusher flaps on the Mythos.

by  |   |  Coffee Science

Just a note on the modified espresso recipe. Gareth is very much persuaded 17g is tasting better on both espresso offerings. Gwilym and I have both favoured 18g for a fair while now so I’m wary of dropping the dose as aroma may drop off. We have been discussing it in Prague. (Here for the Czech BC.) Might have tried 17.5 before going too drastic. The fact remains perceived sweetness is higher on a brew-ratio of 17-34 at the moment so let’s stick to this for a couple of weeks to make sure scores remain high in the journal. Very important we are all on the same page for brew ratio. Please offer up any opinions on this subject. A 17-34 shot pouring in around 24sec with and accidental extra gram comes out in about 34seconds as very much more acidic.

Also note the new clump crusher flaps on the Mythos. This should greatly reduce channelling. It is my opinion any outliers with TDS readings are channelling. If you get a 15-16% TDS, run another test. Look out for shots starting at the back of the basket and moving forwards. A sign of larger particles landing closer to the front of the basket as they are heavier, less arc in their flight out of the throat. With this in view, I’m still asking everyone to manually distribute into the basket in no more than four movements if possible.

I would also ask that we try a period of not tapping. All I see is the coffee getting shunted towards the back of the basket where as no tap at all should also give us an indication of how good the clump crusher is (question the name, I preferred buster). I should point out that Vince Fedele taps, Hoffman taps and Gwilym taps, TAP taps. It is suggested that the square shaped VSTs need a tap to level the coffee into the corners. So I’m proposing a trial period of no tapping. It is extremely technical to get a precise 90degree impact on the bottom of a portafilter, especially with spouts and very especially if there is a rubber mat with bounce. Also the degree of impact is impossible to replicate. Again we need a common stance. If some tap and some don’t we will get a big range of shot times.

Two weeks ago an attempt to get higher extraction from 18g with higher TDS water was seemingly dismissed by consensus as not increasing extraction and adding a milky sourness. Do we indeed have consensus on this? If we up the blend of straight carbon filtered London water with our RO water (approx 11tds) we up the quantity of bicarbonates in our water (think bicarbonate of soda). SCAA recommends 35ppm of alkalinity. We have 50 at 130ppm. Pop a bit of soda water in a coffee or baking soda to get the general idea; soapy an’orrible. 130-150 might be better for speed of extraction in espresso but in London we have this issue of a high proportion of bicarbonates (also known as alkalinity, not to be confused with alkaline, the opposite of acid).

A negative flavour association from a BRAT student over the weekend was pancake batter. Can we try to ascertain if this is anything to do with the lower TDS as we are back at 90ppm. Gwilym suggested pancake might imply a baked roast (too long with low temp) The Langlier index for 80ppm was mildly corrosive so it is starting to look like we are stuck around 90ppm. Though we might start to see an optimum taste/flavour come in around 40ppm (much like the amazing Madran Kaltun I used in the Brewers Cup) but then the langlier index becomes solidly corrosive. To get a usable range we could try adding mineral salts, a la Gwilym’s Cezve Ibrik performance, and using a reservoir, market cart style. That is the next phase of experimentation. Magnesium is pricy, I can tell you. Every house in the UK used to have a reservoir in the attic to keep water pressure steady. This could be oxygenated like a fish tank. Jacob Thue has had this idea for a long time but if we can make great shots at 17g on RO at 90ppm so much the better. £2366 pounds saved on the coffee bill p/a. Gwilym still likes 19g in a 20g VST (larger hole sizes). We can find a consensus by the end of next week. I stress, we are not worried about cutting costs here. It is not a wastage issue, it is a beverage standards issue.