Syphon Dome

[scottlucey]

I'm interested in a discussion on the "Syphon Dome." I've heard both opinions backed, whether or not the dome matters, but I will admit that the best syphons I've made do have this dome shape after the grounds have filtered.



This isn't the best - but I think good enough for reference.

What matters most? Agitation, turbulence, or both?

I also think it's interesting that I find more backing for a side-to-side agitation technique for the sake of saturating grounds quickest, but the only way I've been able to get the dome (and great tasting coffee) is with the circular method, which also takes longer than the side-to-side.

I want some training for the Japanese Syphon Champion - I know he's (she?) out there

[Jim Saborio]

I'm sure everyone agrees that the grinds just need to be saturated with a gentle stir at the beginning of the brew.

The fists start flying when you talk about the final stirs before draw-down.

I'm certain that the stir just before draw-down makes the dome. I never got a dome in the years before I started stirring. Does the stirring help keep the grinds in suspension during draw-down? Does this keep the grinds from slowing the southward flow? Are the suspended grinds less likely to over-extract than a sloppy lake of grinds? Is the dome somehow a more ideal arrangement of the grounds as the coffee passes through?

Maybe Mark could remind us why he thinks stirring is hogwash.

Maybe someone could explain why my wife makes better vac pots than I do... WHEN SHE KNOWS NOTHING AND IS NOT EVEN TRYING!

[Sandy]

Maybe someone could explain why my wife makes better vac pots than I do... WHEN SHE KNOWS NOTHING AND IS NOT EVEN TRYING!

it's got to be a "spouse thing", as my HUSBAND makes better coffee than i do at HOME. Drives me absolutely crazy.

[Aaron Ultimo]

I thought it was all about creating a linear "wave" with a nice wide stirring tool.

[Jason Haeger]

I thought it was all about creating a linear "wave" with a nice wide stirring tool.

The Aeropress paddle gets more love with my Hario than with my Aeropress.

I agree with quick initial saturation being vitally important.

I also agree that the stir before draw-down is what creates the dome, if so desired. I'm not clear on the reasoning for the dome, but it's a check of a lot easier to clean up than a nice even layer of grounds all around.

Here's a BS hypothesis. What if the "mound" enables fines to be trapped by larger particles that might otherwise inhibit southward flow? I haven't done enough testing between the two methods outside of "what makes the mound", and it is assuredly (at least, from my experiences) due to circular stirring (it doesn't take much) just before draw-down.

I really feel now I should do more experimenting with this.

[Jaime van Schyndel]

I also think it's interesting that I find more backing for a side-to-side agitation technique for the sake of saturating grounds quickest, but the only way I've been able to get the dome (and great tasting coffee) is with the circular method, which also takes longer than the side-to-side.

What do you mean, 'takes longer than the side-to-side'?

If you don't elaborate on your methodology, dose/time/stirs, the roasts used, and the equipment, it's tough to see where you are coming from.

From my own experience, the whisking or circle agitation just gets uneven extractions. For some roasts, this can hide some problems or exaggerate others. Thinking about it logically, the depth of the cake effects draw down and an even cake would imply an even draw down. Is there some logic that would imply otherwise?

BTW, our ceramic/cloths naturally have a more domed brew cake than the metal/cloth filters but still no more domed than the natural curve of the filter used.

[scottlucey]

I guess a video would work best on this one. I mean to say that for me it takes longer to saturate all the grounds (initially) with a circular method. Side to side means that you would be agitating/saturating the grounds with a side to side motion, whether it be north south or east west.

I didn't elaborate on other details of methodology like dosage or roast because I only wanted to focus on the dome that can form in the end and whether or not people think it's related to a specific saturation technique. AND whether or not people think the dome is a sign of a well made syphon.

[Jaime van Schyndel]

I recommend an east west east west north south north south for people who buy Syphons at the shop. I do think it is very dose dependent (which is roast/coffee dependent)and since we use a whole lot more coffee than the old methods(for our roasts), it might not be relevant what we think(especially if you have a larger Syphon with a smaller dose).

Many Japanese love the pronounced dome, Taiwanese we know hate it. Both use very different style of coffees/roasts.

edit: So I posted a few bits on the site we had in pocket for awhile so anyone can repeat the method we use. For our current coffees, we use the 3 stir, 90C method detailed. Video shows just how we brew it. http://www.barismo.com/2008/09/syphon-p ... anion.html

[Mark Prince]

I'm certain that the stir just before draw-down makes the dome. I never got a dome in the years before I started stirring. Does the stirring help keep the grinds in suspension during draw-down? Does this keep the grinds from slowing the southward flow? Are the suspended grinds less likely to over-extract than a sloppy lake of grinds? Is the dome somehow a more ideal arrangement of the grounds as the coffee passes through?

Maybe Mark could remind us why he thinks stirring is hogwash.

It's all based on empirical testing, nothing super scientific, but followed methods:

- varied the brew time
- varied the dose
- varied the grind
- varied the heat intensity
- varied the stirring techniques

I think the biggest test I did was with a few local baristas and we had four 3 cup vacpots set up with the same coffee, same grind, same brew time, and did two variances:

Vacpot a had an initial stir only, and low regulated temperature after the kickup
Vacpot b had an initial stir only, and a higher more turbulent heat temp after kickup
Vacpot c had initial, middle and finishing stirs, low heat after kickup
Vacpot d had initial, middle and finishing stirs, high heat after kickup

IIRC, brew time was around 70 seconds (after kickup, each timed on their own), a fairly fine grind.

Favourite by a slim margin was a followed by b. Everyone found c and d to extract too much bitters. Tasting was blind, except for me, and I made no tasting comments till everyone else had.

Now, if you tweaked the grind or brew time, it might make a difference. Then a and b may have fallen short, who knows. I don't have 20 3-cup vac pots and 20 timers, and etc etc to really do a good test.

Mark
PS - we did have some cool looking domes. I have pics and notes around somewhere - I was going to write something up about this on CG, but I thought it'd be way too geeky for the site. But I do these things so I have at least a smidgen of inkling about what I'm shouting about.

PPS. I still haven't found a S/O espresso shot I've really enjoyed anywhere near as much as a blend

[phaelon56]

Is there any qualitative difference between the syphon coffee made in devices with the open top straight walled upper chamber versus the globe shaped top like my Bodum vac pot has? Or is it a matter of convenience and faster cleanup in the commercial environment?

Note: when I started making vac pot coffee the only reasonably thorough source of technique info I could find was Mark's old piece on Coffeekid (from years ago). Based on that information I adapted my technique to add a brief stir at the beginning so that the grounds would get entirely saturated with water just after the onset of brewing but I never touched them after that. The brief stir improved my results relative to a non-stirring technique but I never experimented after that (I'm a leave-well-enough-alone guy for certain processes),

What's the real deal with the "dome"? Is it really just a result that has a strong aesthetic appeal whcih has influenced taste perception or do people really think syphon coffee brewed so as to leave a dome will taste better?

[Luke Shaffer]

I've been following the method as detailed on barismo for about 6 months. The coffee just tastes more intense and flavorful to me when I follow these instructions. I find the coffee more syrupy and the brighter tones more concentrated. The best cup of syphon coffee I've ever had was brewed yesterday. With my Hario I was using a brand new cloth filter (metal inside) and 24g of Intelli's new El Salvador ground to what I would call a pretty fine cone grind. I dropped the coffee at 199F, brew time was just under a minute. The draw down was a little quicker than usual @ 25 seconds, but I used the cold towel method and my dose was a little lighter than usual.

No real dome to speak of, but it didn't matter as it just tasted really really good and I wanted to share my experience. Yeah the dome is pretty sweet to look at, but honestly I've had some nice domes where the coffee tasted kinda nasty. To me it's like latte art- it's one indication of quality but ultimately doesn't guarantee it.

[Alistair]

I love glass filters.

[Mark Prince]

I don't like glass filters much. Fun to look at, but after losing two vac pots over the years to plugged up glass filter kickdowns, not so much fun. Worst was a vintage 1930s GE space age lookin' vac pot. I really miss that one.

Mark

[Jason Haeger]

I agree. I'm not so fond of glass filters either. In concept, it seems like a great idea, but its practice is another thing entirely.

I have had much better luck with cloth filters than with glass.

[Jim Saborio]

Look Jason, I sold you that filter thinking it was going to a good home... I don't want you bad-mouthing it!



Yeah, my Cory rod is also retired, but I'm saving it just in case someone develops a fool-proof method. I guess they're cool if you're really zen and don't mind tossing out several pots while troubleshooting at 7am.

[Jason Haeger]

Look Jason, I sold you that filter thinking it was going to a good home... I don't want you bad-mouthing it!



Yeah, my Cory rod is also retired, but I'm saving it just in case someone develops a fool-proof method. I guess they're cool if you're really zen and don't mind tossing out several pots while troubleshooting at 7am.

Hey, I use it for my larger bodum vac-pot for entertaining. For geeking, I stick to my TCA-2 and a cloth filter.

Most of the time, it hangs out requiring dusting from time to time. Most guests would rather have espresso drinks.

[Andy Schecter]

From my own experience, the whisking or circle agitation just gets uneven extractions. For some roasts, this can hide some problems or exaggerate others. Thinking about it logically, the depth of the cake effects draw down and an even cake would imply an even draw down. Is there some logic that would imply otherwise?

Yes, I think there is some logic that suggests that a domed cake will extract more evenly:

During the drawdown, there tends to be a higher flowrate down through the center than along the sides. That's because there is friction between the moving liquid and the stationary side walls, but no such friction in the center. Consequently, a drawdown with a level cake washes out the center of the cake more throughly than at the sides. A domed cake compensates for this by providing more resistance to flow in the center, evening out the flowrate and washing out the cake more uniformly.

The "ideal" amount of doming and the degree to which it makes a difference are open to experimentation, but the effect is real. Unlike some folks, however, I believe the rapid kind of stirring that produces a dome effect like that in the photo below is going too far.

[Alistair]

I agree. I'm not so fond of glass filters either. In concept, it seems like a great idea, but its practice is another thing entirely.

I have had much better luck with cloth filters than with glass.

I've never had an issue with my glass filter, never one stall or breakage.

I really dislike having to clean and maintain cloth filters, as they tend to taint the coffee depending on how well it was cleaned and rinsed. Overall I would prefer to use fine mesh stainless steel if it was available.

[nick]

I really dislike having to clean and maintain cloth filters, as they tend to taint the coffee depending on how well it was cleaned and rinsed. Overall I would prefer to use fine mesh stainless steel if it was available.

Interesting. I had a conversation with a respected Japanese coffee professional a few weeks ago, who told me that he doesn't like "japanese vacuum pots" because of the cloth filters, for the reasons you mention. He also added that he believes that cloth-filtered syphon-pots were so developed to ameliorate the taste of the low-quality whole-bean coffee that Japan was importing.

I have only a little experience with japanese syphon coffee, but I found his comments interesting.

[Jim Saborio]

I was served a vac pot recently and the cloth filter was so dirty that it actually discolored the brew water. I was assured that the filter needed to have a coating of oils on it much like a portafilter.

Ok, I'll keep an open mind, I thought.

Was the coffee tainted? I couldn't say I noticed anything, but it was the first time I had that particular coffee. It was extremely mild. It did creep me out to have my coffee brewed with yellow water, however. If that's everyone's idea of clean, I say break out the glass rods.

But Nick... I'm confused, how does a cloth filter make the coffee better or more tolerable? Sounds like magic! Is the dude a huge Cona fan? Does he rock vintage pots? Are Taiwanese ones ok?

[Keith]

I have been using a Cona Vac Pot daily for close to a year now. Just recently I had my first issues with the glass rod locking up and the funnel not draining. Shortly after that The funnel was accidently broken. When I ordered the part that had been broken I decided to go ahead and order a cloth filter Vac-pot. After a few weeks of using it daily I have to say I dont really enjoy the cup quality. I luv its ease of use, as I can use it on my gas stove, and I love that it never locks up and has no prob draining. But there is something about that cloth filter that really mutes the cups acidity and clarity that I dont like.

[David LaMont]

I was surprised to learn recently that the siphon world and the espresso world in Japan are (from what I could gather) fairly distinct from one another. It even seemed that there were those who identified themselves as "siphonists" and others who saw themselves as baristas. I would guess that it roots out of the fact that there are siphon-based shops have been doing things the exact same way since the 50's or earlier, which have no espresso machine.

I did have a chance to visit a unique shop in Kobe, Green's Coffee Roaster, that does both espresso and siphon. The owner is a 2 time Japan Barista Champ and also pulls a damn good shot. He is a total one man show--siphon, espresso, roasting, iced coffee, and yes...sandwich maker.

The quality is really poor and the video is cut short because of flickr's 90 sec limit, but here's a link to him making me the first in a series of drinks during my 3 hour stay... http://www.flickr.com/photos/deepsouthg ... 351086821/

[David LaMont]

and speaking of siphonry...

In speaking with Mr. Iwao at Green's, I learned that he only uses gas for his siphon work. According to him, halogen is slower-heating and offers less control. When asked what he prefers, he refers to the shiny brass siphon bar on his counter---that they don't make any longer. There are a few companies in Japan still making gas burner stands, but Iwao implied that they don't have offer as much control.

So I've been thinking about heat sources and started thinking about bunsen burners. That's when I stumbled upon these. It looks like it would make an incredible heat source for some serious vacpot fun. Heck, there's even one for sale on ebay right now.

Anyone with a spare $289 care to purchase it and report to the rest of us?

[phaelon56]

But there is something about that cloth filter that really mutes the cups acidity and clarity that I don't like.

I'm wondering if a mesh filter made from an appropriate inert plastic might be a good option. I have an electric Bodum Santos Lexan type vac pot that was given to me but I don't use it because the brew time is too short and can't be controlled (there is a work-around that involves raising one side of the pot with a shim but it's an inadequate solution).

The Bodum has some kind of nylon mesh that cleans very easily and - in my limited experience - does not seem to harbor residue but perhaps it has other shortcomings?

[url]
http://www.bodumusa.com/shop/line.asp?M ... 2ANWVG3K84[/url]

I have heard a few people mention a preference for the cloth filter over the Bodum plastic filter (Tom Owens makes that comment in the vac pot section at sweetmarias.com) but am curious as to why.