Posted Wed Jul 22, 2009, 3:50am Subject: Re: Using a Siphon Coffee Maker
al_bongo Said:
In short the increase in pressure in the lower chamber is a result of the increasing amounts of water vapour from heating the water to higher temperatures until eventually the water boils.
I don't think anyone is denying that water is going up the tube, they're saying that gas is what's pushing water up the tube. Even the full quotation that you snipped from Mark's article says that. He says:
"Once the siphon coffee maker is assembled, heat is applied to the lower container. As it heats up, some of the water is converted to a gas - water vapour. A gas occupies a lot more space than its liquid or solid variant, and it can expand as more heat is applied. Gas can be compressed, but only to a point, whereas liquids do not compress. The water vapour continues to expand and it seeks some relief from all the compression it's starting to have. The only escape route out of the bottom vessel is the siphon tube traveling up to the top, but the problem is, there's a lot of liquid blocking its way. So what does the gas vapour do? It pushes the water up the siphon tube!"
It is not your opionion this is a fact (at least at the start of the process). No one is disputing this point. Where you seem to be going awry is in the understanding of what makes this happen (see philosogeek's post for the most recent explanation).
Philosopher Senior Member Joined: 13 Feb 2007 Posts: 188 Location: Australia Expertise: I like coffee
Espresso: Silvia Grinder: Rocky
Posted Wed Jul 22, 2009, 4:53pm Subject: Re: Using a Siphon Coffee Maker
al_bongo Said:
You would be wrong. The higher the temperature the faster the vapourisation reaching a max at boiling point.
Perhaps a better word is evaporation rather than vapourisation. It rains a lot is Scotland, but the puddles do eventually evaporate even with our current temp of 19*C.
You will also note that when you heat water or take a bath or shower steam rises from the water at a temperature well below 100*C.
Evaporation: The process by which kinetic energy within a liquid causes molecules on the SURFACE of a vessel to change state into vapour. Boiling poinst: the temperature at which vapour pressure exceeds atmospheric pressure. Gas can form and escape from WITHIN the vessel (boiling)
Posted Tue Nov 9, 2010, 9:35pm Subject: Re: Using a Siphon Coffee Maker
To Michael Prince,
Your post on the siphon from 2008 is a model of clarity and good humor.
These days, though, the trend is to send all the very hot water into the upper globe under the pressure of expanding vapor in the lower globe, then add the coffee, stir in one way or another, and so forth. Perhaps you've already written about this. I can't see any disadvantage to this modern technique. I've been using the Cona and then the Hario ever since I first drank siphon coffee brewed in the Cona in 1978 in a many-starred restaurant in the French countryside; nostalgia alone should draw me to the traditional method.
As I see it, the advantages of the siphon are that, 1) immersion is the most efficient and thorough means of brewing coffee, 2) again, a fine grind is also efficient and thorough, and it's quick, and 3) the temperature of the brewing water in a good siphon seems ideal and automatic. Only this last advantage favors the siphon over, say, a French press--that is, if somebody would only design a French press with a very fine filter that can hold back sediment and allow the use of a fine grind. Maybe that's what the Aeropress does, though in an inconvenient way.
So, the design of a perfect coffee-brewer is easy to imagine. Perhaps the Clover comes close, but now you can't buy a Clover and in any event owning a Clover was always quite expensive. Unless you have 50 antique siphons to sell.
MarkPrince Moderator Joined: 19 Dec 2001 Posts: 5,462 Location: Vancouver, BC Expertise: Professional
Espresso: KvdW Speedster Grinder: Compak K10 WBC Vac Pot: A bit too many Drip: Clive Coffee Drip Stand Roaster: Hario Glass Retro Roaster
Posted Tue Nov 9, 2010, 10:53pm Subject: Re: Using a Siphon Coffee Maker
Hi Jeffrey thanks for writing. It's ironic that you talk about the "kick up, stir" method as just today (earlier this afternoon) I posted a couple of videos via my twitter account:
Which is part of a long term experiment I'm doing to check on this different method (I'll explain a bit below). The current method is add heated water, let water rise halfway in top portion, add coffee, two gentle stirs as water continues to rise, brew for 80 seconds, then a very gentle stir as I remove the heat source.
I say "experiment" because I've found out something over the years about refining a brewing method. Doing it once or twice, following someone else's regimen doesn't necessarily provide better (or worse) results by default. Once or twice usually results in something "different tasting" for me, but hard to sometimes gauge if it is better or worse. Lately, I've been trying to give alternative brewing methods, styles, techniques a longer chance; I'll try a method for a few weeks, see if I see something better or worse with it, how things taste, get used to it, etc etc, then I'll do some head to head testing of an older technique vs the newer one.
In the case of this new brewing technque for siphon, I've already done one head to head with my older style after doing the new method for a while, and I still have to say the older method results in more consistently good brew. The catalyst seems to be the final stir - no matter how gentle I do it, it tends to impart more bitters and "roast notes" to the cup than no end-stirring. I also think adding ground coffee to 200+F water (if you let the top bowl heat up and fill up first before adding coffee) may have some merit; my speculation is that a certain shock happens to the grounds and minimizes excessive acidity and sours from coming out into the brewing water - but that is pure unscientific speculation.
As a result of all this, I may revise my recommended method for brewing siphon; add coffee late, two or three regimented and controlled gentle stirs near beginning of the brew, and zero stirring after.
IMAWriter Senior Member Joined: 4 Jul 2002 Posts: 5,462 Location: Brentwood, TN Expertise: I live coffee
Espresso: Nothing at the moment Grinder: Vario-W,Preciso-Esatto/KyM... Vac Pot: Adcraft SS, Yama 8 cup Drip: Brazen.Chemex, Hario, Clever... Roaster: Behmor 1600, CO/UFO combo
Posted Tue Nov 9, 2010, 11:14pm Subject: Re: Using a Siphon Coffee Maker
MarkPrince Said:
t into the brewing water - but that is pure unscientific speculation.
As a result of all this, I may revise my recommended method for brewing siphon; add coffee late, two or three regimented and controlled gentle stirs near beginning of the brew, and zero stirring after.
Exactly as I have been doing it for about 6 years, as explained to me by our own Craig A, moderator . A while back I tried the "final" stir at the end of the brew time, and found it caused the drop down to slow a bit. Eliminated it.
mir71 Senior Member Joined: 16 Feb 2011 Posts: 1 Location: Asia Expertise: Just starting
Posted Wed Feb 16, 2011, 9:37pm Subject: Re: Using a Siphon Coffee Maker
Good article, if you are looking for soft rich coffee (without bitter taste) try shortening brew time - I add coffee grounds after water has risen then steep for 45s before removing heat - this removes bitter taste that can develop with strong beans
Cerridwyn Senior Member Joined: 6 Jun 2010 Posts: 395 Location: Inland Empire California Expertise: I live coffee
Posted Thu Oct 20, 2011, 4:53pm Subject: Re: Using a Siphon Coffee Maker
When I was a little girl, my mother made her coffee on a percolator on the stove, just like many housewives from the 50's and 60's, later graduating to an electric one. Her sister, on the other hand, always used this contraption on the stove that fascinated me. It was a Silex vac brewer. Like many small children, I loved to watch it brew.
When my mother graduated to an electric drip, my aunt kept her Silex for many many years, unless she could no longer get replacement parts.
Seeing these in fancy coffee houses brings back some wonderful childhood memories. I might just have to buy myself one for Yule.
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