I think you're looking at this the wrong way. There isn't a problem with pourovers being too "slow", the problem is at what point are the filters/brewers slowing the flow/choking the brew. Think about it in terms like this:DamianWarS wrote:yes I agree but this would slow the flow down again wouldn't it? fast flow seems to be this unit's thing
I wasn't aware the problem of pourovers was they were too slow.
Water is flowing through coffee. The coarser the grind, the faster the water will naturally flow, but the less the water will reach the inside of the ground coffee and the less that will be extracted. The finer the ground, the slower the water will flow and the more that can be extracted, but the more opportunities you have for over extracting of particular particles and channeling due to clumping.
First thing you need to help this is a good grinder that is unimodal, because fines play no role in the brewing of coffee, unlike the role they may play in Espresso(not saying they do or don't). You want water to be flowing through particles that are the same size as much as possible so that the water is extracting the same amount of coffee per particle for the most evenness of extraction.
Now lets say you have an even coffee bed. You are now fighting against channeling. Finer coffee grounds create more channels. Your goal is to reduce channeling in whatever ways you can. However- the slower that water flows, the more opportunity the more channeling that can be created.
So now you have the stationary items in your brew- your paper and your brewer. Micro fines stick to your paper, slowing your flow, creating more channeling. So you generally are looking for the FASTER papers, because it implies a) the pores are smaller, so the particles are that much smaller that will choke your brew and b) the paper itself isn't too causing any slowing down of the water.
Now you have your brewer- you basically have the same issue as the water, which is that if the water is slowing down because of the exit paths it has on the brewer, it will channel. The faster the brewer allows the water to escape, the more even the extraction and the less channeling you will see. So with a brewer like the ESPRO, the water has more paths of exit, will flow out faster and gravity will win out. This will create less channels(THEORETICALLY) and you can grind finer, extracting more coffee from each article and hopefully creating tastier coffee.
Gravity is a better invention then paper filters- if you let gravity be the dominant factor in the speed of your coffee brew, and simply using particle size as the thing that is controlling that, you will make better coffee. There really is no such thing as over extracted coffee in a scenario where truly unimodal coffee grinds exist in a world without channeling. We aren't close to the upper limits of how much coffee we can extract currently. Finding ways to help create that unimodal, chanelless environment is the role of coffee equipment. In theory, this is what the ESPRO is doing.