Fellow Stagg XF Dripper - Page 7

February 22nd, 2021, 2:18 am

DamianWarS wrote:Water takes the path of least resistance so as long as it can flow through the filter at any part of it, then it will flow through the filter provided it's alternative routes have greater resistance. Stuff like agitation may contribute to clogging the filter or changing the resistance of the coffee bed. So im sure it can affect bypass and it may decrease it if the filter pours are clogged up along the walls or if flow through the coffee bed has increased to a point that it's easier for water to pass through.

Stuff like the espro bloom may have lots of bypass or partial bypass from the walls of the brewer by perhaps traveling in and out along the walls. After reading Gange I think it has affected how I approach these brewers and filters and I now consider adding a mesh to any flat bottom.

When you seal the sides you are forcing all (or most) of the water to go through the coffee bed and it may not be desirable results but I think with your testing to know if the mesh does anything if you pressed in the folds and tried one with the mesh and one without you will probably get a faster draw down with the mesh. If you're not pressing in the folds then you will never know how much is bypass and how much is going through the coffee bed to determine if th mesh has a positive effect or not.

I added a mesh to the areopress and treated it as a gravity dripper. (So there is the cap, mesh, then on top of it all the filter) and despite the cap have a lot of holes the mesh made the draw down quicker from 7:00 to 4:30. Because the aeropress has no paper filter along the walls there is zero bypass and all the water must travel through the coffee bed. So the mesh made a difference and I'm a believer.

Using the Aeropress with a mesh as a gravity dripper indeed is very interesting. I did try it and it lead to promising results. Indeed the mesh makes the drawdown faster with the Aeropress.

If the Aeropress is used like that, it can not have bypass. Hence it is much better suited for the no bypass style of brewing than the Stagg X. Nonetheless I am interested in the questions I asked previously, to understand better how I could pour to minimize bypass when not folding in the sides of the paper.

February 22nd, 2021, 4:28 am

I did a test today using an aeropress with the normal setup using a paper filter. No coffee just 250ml of water and no plunging. The draw down was 1:00 and it was slower as it got to the last bits. I added the mesh below the filter and did the same test and the draw down was 30 seconds with no significant slow down. So certainly the mesh increases the speed of the drawdown and you know right away because the filter doesn't seal itself to the mesh but with the cap it does.

As for a pouring technique the more the water line goes above the coffee bed the more bypass you're going to have. If you want to keep the stock unmodified paper filters and minimize bypass as much as possible then a pulse pour or very slow pour that keeps the water line low will be your best approach. You can play with the sizes of the holes but I don't see how that will minimise bypass and if anything it will increase it.

I've taken the funnel from the areopress and made a brewer out of it using it with the bottom part of a phin filter. It worked perfectly fine. People think there is a bunch of magic going on with these brewers and it just isn't the case. If you want a stagg x with more holes get a plastic cup about the same size and drill more holes in it and put a mesh cut out at the bottom and you have yourself a stagg x with more holes.

February 22nd, 2021, 10:35 am

DamianWarS wrote:...
As for a pouring technique the more the water line goes above the coffee bed the more bypass you're going to have. If you want to keep the stock unmodified paper filters and minimize bypass as much as possible then a pulse pour or very slow pour that keeps the water line low will be your best approach.
...

Thank you I will try that

DamianWarS wrote:...You can play with the sizes of the holes but I don't see how that will minimise bypass and if anything it will increase it.
...

Interesting, could you elaborate why more holes would increase the amount of water bypassing the filter bed in your opinion.
I would expect it to be the opposite. My theory is, that water sitting in the bottom of the dripper makes the drawdown slower, hence there is more time for water to bypass through the walls of the filter.
With a bottomless or possibly with an Espro Bloom there is no water sitting in the bottom. Hence the drawdown is faster and there is less time for water to bypass through the walls of the filter.

DamianWarS wrote:...
I've taken the funnel from the areopress and made a brewer out of it using it with the bottom part of a phin filter. It worked perfectly fine. People think there is a bunch of magic going on with these brewers and it just isn't the case. If you want a stagg x with more holes get a plastic cup about the same size and drill more holes in it and put a mesh cut out at the bottom and you have yourself a stagg x with more holes.

Both great ideas and I will follow your lead one of these days and try something like that.

February 22nd, 2021, 12:27 pm

coffeeOnTheBrain wrote: Interesting, could you elaborate why more holes would increase the amount of water bypassing the filter bed in your opinion.
I would expect it to be the opposite. My theory is, that water sitting in the bottom of the dripper makes the drawdown slower, hence there is more time for water to bypass through the walls of the filter.
With a bottomless or possibly with an Espro Bloom there is no water sitting in the bottom. Hence the drawdown is faster and there is less time for water to bypass through the walls of the filter

I think these brewers are some what designed to slow the flow and keep a build up of water at the bottom so that it can extract more. If it was uninhibited the flow would be as fast as it can be and I would fear the bypass would increase proportionally.

You could test a series of tests to determine what gives you the best flow by testing a equal amount of water (cold from the tap) with/without mesh, with/without pressing in folds, with/without filter to determine what contributes to flow (I wouldn't even use a kettle, just dump in a load of water)

I would suspect your results would be:
A. Empty brewer [no filter/mesh] - 1st (fastest)
B. Brewer, mesh, filter - 2nd
C. Brewer, mesh, pressed in filter - 3rd
D. Brewer, filter - 4th
E. Brewer, pressed in filter [no mesh] - 5th (slowest)

If true and pressing in the folds slows the drawdown then it means water is passing through the walls of the filter and contributing to increased flow. But this doesn't mean no bypass is better but if that's what your chasing option C is probably your best approach.

February 23rd, 2021, 6:32 am

DamianWarS wrote:I think these brewers are some what designed to slow the flow and keep a build up of water at the bottom so that it can extract more. If it was uninhibited the flow would be as fast as it can be and ...

I believe you are right. Most brewers are designed to slow the flow, but is that actually the right approach? Doesn't this maybe lead to more bypass and cancelling out the extra of extraction that is achieved by longer brewing time?

DamianWarS wrote: ... If it was uninhibited the flow would be as fast as it can be and I would fear the bypass would increase proportionally.
...

This is where you are losing me, you said this already a couple of times. I don't know why you would think that a faster flow/drawdown leads to more bypass, but I would like to understand your thought.
I think we agree that bypass happens through the sides of the filter.
I would assume we also agree that the longer water is sitting in the filter the more water might bypass, e.g. with one big pour in contrast to many little pours.
Furthermore I would assume, that the higher the water is in the filter the more water might bypass, again e.g. with one big pour in contrast to many little pours.
Lets assume we have 2 brewers of the same kind, with the same filter and coffee. One has a mesh and the other has no mesh. Wouldn't you expect the one with the mesh to have less bypass. Which part am I missing, that contradicts that faster drawdown means less bypass?

DamianWarS wrote: ...
You could test a series of tests to determine what gives you the best flow by testing a equal amount of water (cold from the tap) with/without mesh, with/without pressing in folds, with/without filter to determine what contributes to flow (I wouldn't even use a kettle, just dump in a load of water)

I would suspect your results would be:
A. Empty brewer [no filter/mesh] - 1st (fastest)
B. Brewer, mesh, filter - 2nd
C. Brewer, mesh, pressed in filter - 3rd
D. Brewer, filter - 4th
E. Brewer, pressed in filter [no mesh] - 5th (slowest)

If true and pressing in the folds slows the drawdown then it means water is passing through the walls of the filter and contributing to increased flow. But this doesn't mean no bypass is better but if that's what your chasing option C is probably your best approach.

On another note I am not looking for the best way to do a pour over without bypass, I already found it, you proposed it by using a mesh in an Aeropress as a pour over

#66: Post by **DamianWarS** » February 23rd, 2021, 9:04 pm

coffeeOnTheBrain wrote: This is where you are losing me, you said this already a couple of times. I don't know why you would think that a faster flow/drawdown leads to more bypass, but I would like to understand your thought.
I think we agree that bypass happens through the sides of the filter.
I would assume we also agree that the longer water is sitting in the filter the more water might bypass, e.g. with one big pour in contrast to many little pours.
Furthermore I would assume, that the higher the water is in the filter the more water might bypass, again e.g. with one big pour in contrast to many little pours.
Lets assume we have 2 brewers of the same kind, with the same filter and coffee. One has a mesh and the other has no mesh. Wouldn't you expect the one with the mesh to have less bypass. Which part am I missing, that contradicts that faster drawdown means less bypass?

I honestly don't know what would happen if you increased the hole size. My thoughts were if you don't correct the bypass and increase the hole size then why does water want to move through the coffee bed more than it did before? Water still will take the path of least resistance regardless of how big your hole size is. I did a v60 today with a clear brewer and kept the waterline really low and the resulting brew took 12 min long (I guess from lack of agitation). You could see the bypass on the side of the walls coming down and I'm pretty sure if I lifted the whole filter up out of the brewer it wouldn't have increased the drawdown because I reach some sort of threshold with the coffee bed.

coffeeOnTheBrain wrote:On another note I am not looking for the best way to do a pour over without bypass, I already found it, you proposed it by using a mesh in an Aeropress as a pour over

it was a slow drawdown but I never used a mesh and I'm sure that would have increased the drawdown. alternatively, you could just buy a plastic funnel and cut the bottom off so it matches the hole size. Since you're interested here are some pictures from the Aeropress funnel pour over

February 24th, 2021, 4:31 pm

DamianWarS wrote:I honestly don't know what would happen if you increased the hole size. My thoughts were if you don't correct the bypass and increase the hole size then why does water want to move through the coffee bed more than it did before? Water still will take the path of least resistance regardless of how big your hole size is. ...

Thank you, I understand your thoughts better now. The phrase "water takes the path of least resistance" is a little misleading in my opinion. It should rather be "water takes the path of low enough resistance" but that doesn't stick

Imagine a dripper with 2 holes, one is covered with a filter. The water would not exclusively run through the hole with no filter i.e. less resistance, but both holes as long as the pressure from the water column is high enough to force the water through the filter.

I realize that I get more and more off topic. Maybe I will make a new topic to discuss fluid mechanics in drippers. It surly will be as popular as the other topics I started lately

DamianWarS wrote: ...
I did a v60 today with a clear brewer and kept the waterline really low and the resulting brew took 12 min long (I guess from lack of agitation). You could see the bypass on the side of the walls coming down and I'm pretty sure if I lifted the whole filter up out of the brewer it wouldn't have increased the drawdown because I reach some sort of threshold with the coffee bed.
...

I think the physics of water flow in a dripper are pretty complicated. In your example it might be the case that the pressure from the water column was just not high enough to force the water through the coffee bed. Maybe it was just ground to fine for this kind of pour over technique. Or maybe something completely different

DamianWarS wrote: ...
it was a slow drawdown but I never used a mesh and I'm sure that would have increased the drawdown. alternatively, you could just buy a plastic funnel and cut the bottom off so it matches the hole size. Since you're interested here are some pictures from the Aeropress funnel pour over

Thank you looks interesting!