For the Clever dripper, it seems like the common adjustments are grind fineness, steep time, and coffee-to-water ratio. For acidity reduction, would it help to lower the water temperature? We tend to stay in the range between 190ish and low 200's. I remember some Aeropress recipes using 180F. Sure, 20% extraction is key. But I suspect there are more dimensions to this equation than just the extraction percentage. Just to take extraction to the extreme, a cold brew 20% extraction will taste very different than a hot drip 20% extraction (hypothetically brought to the same temperature when consumed).
Now going back to the Clever, I suppose if you brew at a lower temperature with a slightly longer steep time, you might have a further easier time without being overly careful with grind fineness and evenness, and you'll get a sweeter cup. Another thing to experiment with is steep a shorter time with half the water, begin the drawdown, then add the other half of the water through the Clever like you would a V60. It bares some resemblance to Tom Owen's experimental recipe I saw on youtube. YMMV.

Personally, I don't think 20% is key, if it's a target/start point you want to hit with a Clever steep then great, but I prefer mine further on than that, for increased sweetness. This takes tens of minutes at a fine grind, 65-70g/l, and the steeping coffee is 60C or lower by the end of steep. Not everyone will enjoy coffee at that temp.

Have you achieved a 20% cold brew immersion extraction? How long did it take? Most folk don't steep cold brews long enough to hit 20% & overdose to get something they like at a lower yield in a shorter time.

I rinse my Clever with water straight off the boil, then fill...even then it loses heat quickly, lower strike temps may be worth a try but will likely result in tepid coffee & a low extraction?

Didn't Tom Owens bypass brew in that example, 20g coffee to 180g water, draw down then bypass (If we're talking about the same video, Kenyan brew?)? I think that could be the most practical route to reducing acidity, but doubt you'll be getting a high extraction yield (which may not bother you). I used to do this when making 600-700g of final beverage from a single Clever brew, ~40g of coffee, steep as normal then bypass to full weight...sweet, syrupy cup, but surpressed brightness.

The partial steep/long prewet, then rinse can work great, but you need to be more careful dialling in grind, more like a straight drip brew...which is also an option with the Clever.

Acid in brewed coffee is an interesting question I ponder frequently, in part because of my obsession with Ethiopian varietals, the same origin that caused Brian to open this thread. Sometimes I get a coffee that's so acidic it's undrinkable, like biting into a plum that's sour. What do you do with the plum? I'll tell you what you don't do: try and figure out how to bite it differently so that it's less sour in the mouth. You toss it and move on. There's only so much you can do with grind, temp, and time to mitigate what's already in the bean. I am not saying give up on trying some grind tweaks to optimize your situation, but to a point. There comes a time in the experience curve of all coffee geeks that you have to trust that the problem is the bean and not your technique.

A coffee that is so sour it is undrinkable suggests a degree of under-extraction/a severely underdeveloped roast. Counter-intuitively, pushing extraction on can reduce the acidic character, even though you are increasing the total acids in the coffee. Pulling back extraction further can tame it too, I suspect that's what is happening in Tom Owens' high dosed Kenyan example.

Another way to tame acidity might be to use water with a higher bicarbonate content (maybe ~150mg/l vs 40mg/l), too high and the coffee can be chalky, but sometimes it can be creamier, with less pronounced brightness, without destroying origin character.

MWJB wrote:
Another way to tame acidity might be to use water with a higher bicarbonate content (maybe ~150mg/l vs 40mg/l)

What a great idea. It never occurred to me, but water is indeed a variable, and one that contains a buffer in the form of bicarbonate. I will check out some bottled waters and the next time I get a coffee on the very acidic side, I'll try the higher bicarb water and see if I can taste a difference with all other factors equal.

You can build a pour-man's sieve with paint strainer mesh from your home improvement store and canning jars with the bands taped together. It actually works pretty well and you can use 4 oz jelly jars, 8 oz canning jars, or whatever size fits your needs.



I haven't used mine in quite a while, it's at work but I upgraded from a Hario Mini mill to a Lido 2 and haven't felt the need for the sieving, but I also haven't been using the clever dripper much either.

I'm slightly late to this thread, but I find myself in very similar situations as the OP and discussion, using the Bonavita Immersion Dripper. I found my best results with more fruited Ethiopian coffees to come from using the Immersion Dripper as more of a pourover or a hybrid, experimenting with keeping the valve fully open or partially open leaning more towards the pour over spectrum. My hypothesis is this extracts less, bringing out more of the lighter flavors and less of the caramels. The sieve now has me intrigued that I might be able to achieve a more amplified 'bolder' version of the same flavor profile by allowing it to steep/brew as intended, is that the idea?

And I'm also very curious as to at what point or when the experts start playing with brew temperatures to influence this as well. Tom- do you typically leave your kettle set at one temp and adjust by grind, time, or dose?

One thing I have found to be counter-intuitive is that the general rule of thumb is to brew lighter roasted coffees at higher temps (203-207F), but a lot of the time I find I loose a lot of the floral and fruit flavors when doing so, and have often times favored lower 197-201F-ish temps on many of the Ethiopians I have used. I also noticed that many cafes are not using PID kettles but usually using a hot water dispensing system to fill up goose-neck kettle, which leads me to believe that by the time they fill the kettle and start brewing, they are in the lower brew temp range as well.

Regarding brewing certain coffees at lower temperatures, I've found that coffee from Ethiopia benefits from a 198F brew in my BraZen where I brew a lot of other coffee at 200F. There's a very noticeable difference in sweetness when lowering the temps on coffee from Ethiopia and I think it's specific to the coffee or the origin and not so much the degree of roast.

gophish wrote:The sieve now has me intrigued that I might be able to achieve a more amplified 'bolder' version of the same flavor profile by allowing it to steep/brew as intended, is that the idea?.

Sieving out fines won't give a bolder steep (compared to pourover), at the same ratio, unless you go much finer on the setting. In effect, sieving out the fines will give an overall coarser setting which will equate to less bold, unless you increase the dose to compensate &/or increase steep time.

Correct, maybe I misspoke- I think I often times prefer these coffees as more of a pour over, perhaps because it's biasing a lower extraction than if I did everything the same and did a full immersion brew. So, my hypothesis was that if I sieved out the fines (which would be over-extracted) I could brew using the immersion method to more fully extract the desirable flavors. Maybe I'm incorrect with this thought process though.