I have been playing with my cotton filter and hand grinder for , approximately, 1.5 years. At first, things went well, lovely aftertaste, aroma and etc. Then suddenly one day all the good things disappeared. Yeah in one single day!
I thought it was the beans so I talked to my roaster whether the sudden change is related to the beans or not. For sure the beans were fine because some casual cuppings were done and the cups were absolutely tasty.
We then came to a conclusion that it could be 1) water temp which I kept constant, 2)grind which I kept constant, 3) brew time which I thought it's okay. I played with water temp for quite a long time since I had the experience of getting strange coffee because of wrong temperatures. Alright, I get overextracted and underextracted cups and it seemed that there were no intermediate cup profiles!
One day, I heard my roaster saying that for cotton filter, the grind should be 1notch finer than what I had been using. I adjusted the coarseness and I got some slightly stronger cups but they were nowhere close to what I had at first. I keep trying and trying for maybe 9 months or, perhaps, 1 year (doh!) .
If you can withstand the boredom of this post and have not closed your browser, you might say, ' Hey dumbhead, you never checked your brewing time!'
Indeed, I never measured the time precisely and it was not too long ago that I knew 0.5g of grounds can have serious effects on the final cup. Last week I decided to measure it seriously with a stopwatch and I was absolutely shocked. I always thought that the brewing time was pretty much okay, i.e. 3mins 160ml . Heck no! It took 2mins only to finish one brew, which is WAY TOO FAST. I then use the finest adjustment on my hand grinder and it took 2min 20 sec. Nope, not ideal and the cup sucked.
I reluctantly put my hands on my super jolly to grind much finer. I never used SJ for filter coffee since I hope to use a 'cooler' grinding method so more aromas can be preserved. I managed to get a 3min brew after 2 or 3 trials and the cup was pretty good. Although there are more things to experiment but at least now I know why all different parameter changes never worked! The grinder is already too old and cannot do the job well. That means I need to buy one more hand grinder.
Lesson learned: Check parameters precisely, counting in heart is way too stupid.
Yes, filter coffee is less demanding than espresso, but it doesn't mean you can do it casually
Happy Brewing!


P.S: I hope my grammar is not too broken :P