Cory Filter Rods

[Bertilak]

A while back I gave up on my Yama because I was getting inconsistent and unsatisfactory results. I heard that a Cory filter rod might help so got a hold of one. So far, I have made one trial pot with the Cory rod so it is impossible to say if the results are consistent or not!

I did notice three things:

1. The same amount/grind of coffee beans I use for my Technivorm Moccamaster resulted in fairly week brew in the Yama. This I can adjust for. The next two, I don't know ...
2. The resulting coffee was, as I feared it would be, very foggy looking, meaning the filter wasn't as effective as the paper filter in the drip machine nor as the cloth filter I have used in the past in the Yama.
3. The brew had a "funny" (stale?) taste -- perhaps I didn't get the water hot enough or perhaps the aeration from the "gurgling" (see below) messed things up. I know oxygen/air is the enemy of coffee. This is similar to the unsatisfactory results I was getting before and, without much conviction, blamed on the cloth filter.

My brewing technique is:

• Bring the water to a near-boil in the bottom pot.
• Turn the heat to low.
• Insert the assembled and filled top section.
• Let the water all rise (takes maybe 30 seconds).
• Let the brew "gurgle" for a minute. This is per the instructions that came with the Yama.
• Remove from the heat.
• It sits off the heat for a minute or so before the brew starts to suck down to the bottom which takes another minute or so.
• Pour and serve. :)

My trial run was with the same coffee I used this AM. It was brewed and delivered to me Tuesday and fresh ground when I made the coffee. I use fairly course grind marked for drip on the grinder.

[SiBurning]

I don't let it gurgle. The steam is too hot and makes a sour cup. You get the same sour taste if you extract espresso too hot. The hard part is finding a way to keep the water in the top long enough without letting it steam through.

[Jim]

Your grind may need to be a little finer also.

[Jasonian]

I don't let it gurgle. The steam is too hot and makes a sour cup. You get the same sour taste if you extract espresso too hot. The hard part is finding a way to keep the water in the top long enough without letting it steam through.

Just to clear something up, the "gurgling" doesn't really mean a whole lot except that gas is escaping from the bottom chamber. It's a good thing. If it does not, then the draw-down may stall.

Over-extraction via prolonged dwell time or too much thermal energy results in bitter flavors, not sour. Sour flavors occur when the brew temp is too low or the dwell time is inadequate.

I've mentioned this in another thread, but you might allow the water to stabilize in the upper chamber (use a thermometer if you need to) before adding your coffee. Stir only enough to fully saturate the grounds, and match the dwell time to the grind setting. (coarser requires more time. Finer requires less time. Vac-pots take a balancing act of sorts in this variable.)

"weak" coffee is a function of the coffee/water ratio, but folks will often use the words "weak" or "strong" in reference to bitterness (extraction rate).

I'm guessing this is probably the case if you are happy with the same ratio used in a different brew method.

[Bertilak]

Just to clear something up, the "gurgling" doesn't really mean a whole lot except that gas is escaping from the bottom chamber. It's a good thing. If it does not, then the draw-down may stall.

Over-extraction via prolonged dwell time or too much thermal energy results in bitter flavors, not sour. Sour flavors occur when the brew temp is too low or the dwell time is inadequate.

I've mentioned this in another thread, but you might allow the water to stabilize in the upper chamber (use a thermometer if you need to) before adding your coffee. Stir only enough to fully saturate the grounds, and match the dwell time to the grind setting. (coarser requires more time. Finer requires less time. Vac-pots take a balancing act of sorts in this variable.)

"weak" coffee is a function of the coffee/water ratio, but folks will often use the words "weak" or "strong" in reference to bitterness (extraction rate).

I'm guessing this is probably the case if you are happy with the same ratio used in a different brew method.

In thinking about this, the gurgling *should be* mostly water vapor so perhaps that is not directly over-oxygenating the brew although the turbulence might pull in oxygen from the air above the brew in the top section. That's probably not a big factor.

By weak I meant watery. The same coffee/water was OK in the Moccamaster but that is probably because there was a longer dwell time. The Moccamaster takes about seven minutes to get all the water through and the Yama is probably about half that.

I would say the flavor was more sour than bitter. Too low a temperature was my first suspicion.

So, more beans, hotter water and a little longer dwell time might do the trick! A finer grind might help but I am already getting more "dust" into the brew than I want. I use a burr grinder.

[mckolit]

If you're using the cory filter rod, you're definitely going to get more fines in your cup. If you want a clean cup, you need to use a cloth or paper filter or just get used to chewing the last few sips of your coffee.
If you're getting off flavors in the cup, you might need to clean your grinder and see how that affects the flavor. You might be getting some rancid oils built up on your burrs.

[Jasonian]

In thinking about this, the gurgling *should be* mostly water vapor so perhaps that is not directly over-oxygenating the brew although the turbulence might pull in oxygen from the air above the brew in the top section. That's probably not a big factor.

By weak I meant watery. The same coffee/water was OK in the Moccamaster but that is probably because there was a longer dwell time. The Moccamaster takes about seven minutes to get all the water through and the Yama is probably about half that.

I would say the flavor was more sour than bitter. Too low a temperature was my first suspicion.

So, more beans, hotter water and a little longer dwell time might do the trick! A finer grind might help but I am already getting more "dust" into the brew than I want. I use a burr grinder.

Any results yet?

[Bertilak]

Any results yet?

No -- I set it aside for now. Seems there is no cure for the Cory filter rod making a muddy cup other than getting used to it.

I had already tried just about everything with the cloth filters. I do have two more ideas to try while using the cloth filter but am not up to messing with this right now:

1) Get the water hotter before putting on the top section. I was getting the water up to 200 degrees based on a very good cooking thermometer as that is the generally recommended temperature. Perhaps it cools significantly by the time it makes it to the top. Maybe if the water is already at a simmer I'll get a better temperature for brewing.

2) Follow the instructions that came with it to the letter. These don't seem right as they say to assemble the whole thing first and then put it on the fire. I believe this is how I started and decided it was wrong because the water "went north" much too soon.

I could also experiment with the time I leave it on the fire. Perhaps a longer brew time will help. There are just so many friggin' variables.

My Moccamaster is fast, consistent and makes a great cup so I am back to that as my go-to coffeemaker.

[Commander Quan]

One thing technique wise, I've always put the whole thing together with coffee in it and then put it on the stove and let it boil, after it flows to the top chamber I'll turn the heat off but I leave the heat on Medium the whole time until then.

Are you grinding the beans yourself or are they pre-ground? I found that the setting that I normally use for my drip coffee to be the best in the VacPot as well.

Even though you are getting some grounds/sludge in your coffee if it's anything close to what I have it's still a lot less than in my French Press so that's a bonus.

[Bertilak]

One thing technique wise, I've always put the whole thing together with coffee in it and then put it on the stove and let it boil, after it flows to the top chamber I'll turn the heat off but I leave the heat on Medium the whole time until then.

Sounds like you are recommending my second approach. It has actually been a long time since I did that so maybe that's the secret.

Are you grinding the beans yourself or are they pre-ground? I found that the setting that I normally use for my drip coffee to be the best in the VacPot as well.

Yup -- fresh ground on same setting as my Moccamaster auto-drip machine.

Even though you are getting some grounds/sludge in your coffee if it's anything close to what I have it's still a lot less than in my French Press so that's a bonus.

That's why I don't like French Press.