Freshly roasted coffee is good. No complaints there, we don’t want to drink stale coffee. But for me, there are times where I need to use a freshly roasted coffee. It sucks even more when its for espresso, for example, for QC, baristas receiving their competition coffee, but its fresh and are itching to taste it, or you only have freshly roasted coffee at home.
It doesn’t sound like a dilemma of some sort, but trying to dial in, and pulling great tasting shots; out of super fresh coffee is quite challenging.
There always seems to be a certain flavour that’s present when you make an espresso using a fresh coffee, and its quite hard to get rid of. What can you do? Well, you can’t force the coffee to degas and settle, and opening a bag or not sealing them to let it degas quicker is a bad idea. When CO2 is released from the porous walls of roasted coffee, so does the many volatile compounds that make up the lovely aromas. Also, adsorption of oxygen and moisture increases the rate of oxidation, thus, ‘damaging’ the quality of the cup.
With the frustration I had, I wanted to think of a way to use fresh coffee but not by compromising on quality. I think I found a way, but please note that this method isn’t suitable for a cafe, needing to go through 5kg of fresh coffee.
All you need is an Aeropress filter.
It seems that when I place a aero press filter on the bottom of the basket, then dose and tamp like you normally would, then extract the coffee, you yield an espresso which is clean and sweet, unlike the harsh, roasty finish you get from freshly roasted coffee.
It seems that the aero press filter removes the bitter qualities in the cup, and what’s noticeable is the colour of the crema. Filtered espresso is way lighter, and it seems that the paper filter restrained fines ending up in the cup. Fines and crema tastes awful, by removing these, it seems like the espresso was free from the bitter and roasty aftertaste.
I wanted to know how the filter affect the overall extraction of coffee. So by using the same amount of dose, time, temperature, I pulled 5 shots each of non filtered espresso and filtered espresso, and measured their EXT% and TDS%.
Here are the parameters:
Machine: Synesso Hydra
Basket: 20g VST
Coffee: Square Mile RED BRICK Roasted on 28th Jan
Regular espresso shots:
So, except for shot number 3 , they are pretty consistent. They tasted quite nice, fruity with creamy body, but had this bitter, roasty notes on the after taste.
Espresso shots with aero press filter:
It showed that with the aero press filter in the basket, with no change in grind setting or dose, it produces shots with bigger mass. What’s more interesting is that, eventhough shots are bigger, and extraction % higher, the TDS% were similar to shots without filters, which pulled shorter shots.
The filtered espresso tasted slightly cleaner, had more complexity and balance. I really don’t know why this is happening. I don’t know whether the psychological affect of ‘This is going to taste better because its filtered’ is kicking in and playing with my palate, or the aeropress filter is altering the extraction in some way. It’s interesting that, Shot number 3 from regular espresso has 2% difference in TDS compared to a similar shot (in mass) in filtered espresso.
Definite thing is that, visually, the shots pours differently, the filtered shot is much more streaky, and the viscosity of the shot is lower than the normal shots.
5 shots each might not be enough data to justify anything, but,I would love to hear from others what they think!