lately, I have been getting myself familiar with some of Jonathan Gange's blog. What drew me there was his discussion and experiments about what he calls byass and for those who don't subscribe to his Patreon he has an open blog where he talks about it. Bypass roughy is the water that passes through the paper filter prematurely and exits between the filter and brewer walls. You can see this happen in a transparent V60 brewer, while the brewing is going on you can see drops of water flowing along the walls bypassing the coffee bed. Bypass happens when the filter is lifted from the walls of the brewer and this is why your V60 has ridges and if you removed them the filter seals to the walls and the flow would significantly slow down, so you could argue the V60 uses bypass as a part of its design.

Gange seems to be on a quest to control the bypass as much as possible and has preferred the Stagg [X] brewer but adds a cutout tea strainer mesh at the bottom to encourage flow as well as presses the folds of the paper filter in to discourage bypass. So I've done my own tests to confirm this. I don't have a Stagg but I've used an Aeropress as a gravity dripper since there is no risk of bypass and added a cut-out mesh between the bottom cap and the paper filter. Even though the cap has a pile of holes in between the holes is a flat surface that the paper filter seals to and flow then only happens concentrated at the holes. The added mesh lifts the whole filter up and draw down was much quicker so this broadly proves Gange's point about bypass or being able to optimize the flow where you want it and it performed so well I've kept the mesh in there for normal Aeropress brews.

So is the goal to have a bypass-free optimized flat bottom brewer? I can't help but think if guys like Gange and Rao are modifying their brewers to perform better why doesn't someone just make a brewer that already performs in the ways these guys want? it seems the perfect brewer according to these guys is a flat bottom with a factory-installed mesh insert so the paper filter doesn't seal to the bottom to encourage flow but also ridgeless walls so the paper filter can sufficiently seal to the walls to restrict bypass. Does this sound about right or what other things can we do to our brewers to make them better?

I don't know how you'd make a cylindrical paper filter with a flat bottom and no pleats. The paper starts out as a flat sheet of paper on a roll. For regular pleated filters they just punch out a circle and pleat the sides. For a conical filter they cut out a more or less semi-circular shape and bond the straight sides together. I suppose you could make a tube and bond it to a circular bottom, but that's getting pretty complicated = expensive. Also, the cylinder would need to match the id of the holder pretty much exactly or you'd get wrinkles, or it wouldn't touch in which case you'd get lots of bypass.

If the "bypass" (according to the above definition) is a problem, then Kalita Wave, and almost all filter brewers that use ridges, especially Origami, will have problem. And Aeropress will have no "bypass" at all. That does not seem to agree with my experience.

I was thinking about this since I have seen more and more about using v60 filters in an origami. It's funny to me because the Origami was created with the folds so the filter would adhere to the brewer.

Using the v60 recreates the problem that the origami set out to solve.

Clearly this is not 1 for 1 because you have to consider cone shape v flat bottom. But it is interesting and kind of funny at the same time.

I know little about bypass and its benefits or harms to perfecting the brew, but could you not brew a V60 in something like a Chemex to get rid of the problem of ridges? Or use some other generic glass cone dripper from your local super store?

yvrdennis wrote:I don't know how you'd make a cylindrical paper filter with a flat bottom and no pleats. The paper starts out as a flat sheet of paper on a roll. For regular pleated filters they just punch out a circle and pleat the sides. For a conical filter they cut out a more or less semi-circular shape and bond the straight sides together. I suppose you could make a tube and bond it to a circular bottom, but that's getting pretty complicated = expensive. Also, the cylinder would need to match the id of the holder pretty much exactly or you'd get wrinkles, or it wouldn't touch in which case you'd get lots of bypass.

the Aeropress concept I think could be a starting point with a cap that secures in place and a flat circular filter. This would of course eliminate all bypass since there is no filter along the walls which may not be the best result.

dukeja wrote:If the "bypass" (according to the above definition) is a problem, then Kalita Wave, and almost all filter brewers that use ridges, especially Origami, will have problem. And Aeropress will have no "bypass" at all. That does not seem to agree with my experience.

the bypass definition is my paraphrased understanding of it but you will have to check out Gange's blog post where he talks about it to get your understanding. Gange was pressing in the folds of the filters to mitigate bypass and using a mesh at the bottom to encourage flow where he wants it. In that blog, he uses a 3D print of a ridgeless cone brewer as well as a glass V60 with an Aeropress filter held on with an elastic at the bottom and both significantly slowed down drawdown because the bottom is a bottleneck and the smallest surface area and he suggests you need a large flat filter area proportional to the coffee bed. I myself went to my local plumbing store and bought a 3 inch PVC cap with several holes in it, similar to the Aeropress. I attached a small 3 inch PVC pipe on it, added a cutout mesh and cut-out filter and tried a pour-over but I have yet to get the result I want. It seems no matter how coarse I go, sifted or not, the brew takes about 6:30 min and I wanted to get it down to about 4 min. This was an example of a larger flat surface area relative to the coffee bed as Gange suggests but I haven't been able to get results I would brag about. I'm getting another 3-inch flange PVC pipe fitting with a ridge on the inside for the 3-inch pipe to sit on. I'm going to use that ridge to silicon seal a mesh in place and then put a paper filter on top of that. This will basically be a 3-inch hole with a mesh inside (the flange part lets it sit on a cup) so it should allow as fast as flow as possible only restricted by filter and coffee bed itself but I don't think I'll get faster times with it because I don't think the size or amount of the holes are the thing slowing it down.

In my V60 pouring the water rarely gets above ground (only when I tried to touch the edge of grounds for less than a few seconds). If one pours correctly, there is no "bypass" in that cited article. My total drawn down time is about 1:40-2:00 with 8g of grounds. It is so strong that I have diluted it down so that the Brix% would fall into normal range. Just observation from another point of view.

coopachris wrote:I know little about bypass and its benefits or harms to perfecting the brew, but could you not brew a V60 in something like a Chemex to get rid of the problem of ridges? Or use some other generic glass cone dripper from your local super store?

gange's experimented with a ridgeless V60 but because it has a small opening relative to the coffee bed it clogged the brewer and didn't work out so the cone shapes seem to need a level of bypass to work. I don't have the Chemex but it's unusual method of folding a large filter paper with double layers on one side may contribute to a form of bypass, it also has a larger hole. Gange seems to prefer a column of water like what the Stagg [X] has. The Stagg has smooth walls and he adds a mesh at the bottom for better flow. He presses the filter paper in to midigate bypass as much as possible but I wonder if its a similar effect as the Chemex with its multi-layers of filter and perhaps 100% bypass free is not the best option.

dukeja wrote:In my V60 pouring the water rarely gets above ground (only when I tried to touch the edge of grounds for less than a few seconds). If one pours correctly, there is no "bypass" in that cited article. My total drawn down time is about 1:40-2:00 with 8g of grounds. It is so strong that I have diluted it down so that the Brix% would fall into normal range. Just observation from another point of view.

there still will be a level of bypass that may be happening but what you're doing is also what Gange suggests to keep the water level down with a brewer like the V60. Water is passing through the coffee bed but perhaps not all the water right to the bottom and water may be escaping at all parts of the filter that the water comes in contact with. If the resulting cup is too strong then you can use water to get it to a more desired strength or dose down which saves you coffee in the long run and has a lower environmental impact. in a cafe setting the difference of 1gr of coffee can be a savings of 1 kilo of coffee a week depending on the volume of customers. for the year it would be hundreds of dollars saved but only if the method can be as time efficent. 10 min brews would probably waste more money than save.