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Date: 25 Aug 2007 15:35:03
From:
Subject: Stove top espresso
I found a VeV Vigano stove top espresso maker at the Salvation Army
and have been doing some experimenting with it. It is about 5 inches
tall, make of stainless steel with brass handle, and makes a single
shot of espresso. I saw the steam escape valve working today so I am
happy that I won't be grenading myself in the attempt to make a
coffee. One of the problems however, is that the product is not very
hot when it is ready. Could a new seal improve how hot the espresso
gets? The seal seems okay but this is an old device, looks like at
least 30 years old. I have been making coffees by adding hot water to
the shot of espresso, which I must say, tastes phenomenal.
Any info or tips greatly appreciated.


Byron





 
Date: 17 Sep 2007 05:15:47
From: CoffeeKid
Subject: Re: Dave? S'that you?
On Sep 16, 8:19 pm, Barry Jarrett <ba...@rileys-coffee.com > wrote:

>
> Holy smokes! I was just scanning through some past messages and
> noticed Bogiesan!
>
> Dave?

Yikes - The Bogiesan! Could it be true?

Mark




 
Date: 04 Sep 2007 20:53:23
From:
Subject: Re: Stove top espresso
Cool, never understood this part of the stovetop's physics. Thansk for
the explanation.
My first stovetop unit was a 1950 vintage Vesuviana. The water had to
travel quite a distance through a rather large tube and then a filter
cup similar to a portafilter. Wonder if all of that made a difference
in the higher overall temperature at the business end?

I used that rascal to make 200 Vesuvi-pots of terrible coffee before I
started to remove the device form the stove as soon as coffee started
to drip from the filter basket. This seemed, at the time, to prevent
steam from passing through the grounds and produced a much more
interesting little pot of very strong coffee.

Then came the Krups, the Gaggia, the Salvatore.

david boise ID


> It is very difficult to push water that is too hot through the coffee in
this type of mocha pot as the pressure required to push the water up
the
tube, through the cofee and up the next tube is so low.

Whe water is boiling its saturated vapor pressure is one atmosphere.
One
atmosphere in water column is about 34 feet and for the mocha pot the
water
only needs to be raised up 5 inches or so which requires a meager 0.18
psi
or so to do. The saturated vapor pressure of water at 100 F is
already up
around 1 psi, and if ambient is say 70F then the SVP difference is
already >
0.5 psi, more than enough to push the water up through the grounds.
So what
happens usually in a mocha pot is low temperature water gets pushed up
throuigh the grounds initially and may end up in the top at
temperatures as
low as 100 F which as you note is way cooler than you want. <




  
Date: 16 Sep 2007 22:19:34
From: Barry Jarrett
Subject: Dave? S'that you?
On Tue, 04 Sep 2007 20:53:23 -0700, bogiesan@mac.com wrote:

>Cool, never understood this part of the stovetop's physics. Thansk for
>the explanation.
>My first stovetop unit was a 1950 vintage Vesuviana. The water had to
>travel quite a distance through a rather large tube and then a filter
>cup similar to a portafilter. Wonder if all of that made a difference
>in the higher overall temperature at the business end?
>
>I used that rascal to make 200 Vesuvi-pots of terrible coffee before I
>started to remove the device form the stove as soon as coffee started
>to drip from the filter basket. This seemed, at the time, to prevent
>steam from passing through the grounds and produced a much more
>interesting little pot of very strong coffee.
>
>Then came the Krups, the Gaggia, the Salvatore.
>
>david boise ID
>


Holy smokes! I was just scanning through some past messages and
noticed Bogiesan!


Dave?



  
Date: 05 Sep 2007 21:22:46
From: Johnny
Subject: Re: Stove top espresso

<bogiesan@mac.com > wrote in message
news:1188964403.635747.138250@50g2000hsm.googlegroups.com...
> >Johnny wrote
> > It is very difficult to push water that is too hot through the coffee in
>> this type of mocha pot as the pressure required to push the water up
> >the
> >tube, through the cofee and up the next tube is so low.
> >
> >Whe water is boiling its saturated vapor pressure is one atmosphere.
> >One
> >atmosphere in water column is about 34 feet and for the mocha pot the
> >water
> >only needs to be raised up 5 inches or so which requires a meager 0.18
> >psi
> >or so to do. The saturated vapor pressure of water at 100 F is
> >already up
> >around 1 psi, and if ambient is say 70F then the SVP difference is
> >already >
> >0.5 psi, more than enough to push the water up through the grounds.
> >So what
> >happens usually in a mocha pot is low temperature water gets pushed up
> >throuigh the grounds initially and may end up in the top at
> >temperatures as
> >low as 100 F which as you note is way cooler than you want. <
> >
> Cool, never understood this part of the stovetop's physics. Thansk for
> the explanation.
> My first stovetop unit was a 1950 vintage Vesuviana. The water had to
> travel quite a distance through a rather large tube and then a filter
> cup similar to a portafilter. Wonder if all of that made a difference
> in the higher overall temperature at the business end?
>
> I used that rascal to make 200 Vesuvi-pots of terrible coffee before I
> started to remove the device form the stove as soon as coffee started
> to drip from the filter basket. This seemed, at the time, to prevent
> steam from passing through the grounds and produced a much more
> interesting little pot of very strong coffee.
>
> Then came the Krups, the Gaggia, the Salvatore.
>
> david boise ID
So to back up the theory with a quick experiment I brewed up a couple of
mocha pots monitoring with a bead thermocouple.
The first was from cold water, about 4 oz down below to start. around 20g of
cofee ground a little coarser than for espresso, espresso is around 5.3 and
I was using 6 on a mazzer mini. The mocha pot is a stainless Carmencita
Lavazza.Over gas flame on medium low.

First thing I noted was that the metal in the upper chamber near the edges
was geting hotter much quicker than in the middle, as you'd expect.
The first coffee appeared up top coming out at a temp of around 150F.
Sputtering started at about 190F and although I pulled the unit off the heat
at the first sign there was some momentum built up and it steamed the brew
up top raising the temp up around 200. It was a bitter brew but then I was
using old throwaway beans for the experiement.
Next I tried preheating the water to 180 before putting the top on. Coffee
started coming out at around 190F and I pulled it off the heat several
times to avoid the boiling that can come at the end if you leave it too
long.
I am surprised that in the first test the initial coffee was as high as 150F
as doing the same thing on an Atomic a ways back from cold the coffee
started dripping around 105-110F if I recall correctly. I don't know why
that would be so much higher than on my Atomic.
I think you might get initially hotter coffee if you start with hotter
water but it is much harder to avoid boiling the coffee with the steam at
the end as it all goes that much faster. A real balancing act but depemds a
lot on the type of mocha being used.
IME vac pots suffer the same problem of cool water going north too son if
you start from cold.




 
Date: 02 Sep 2007 19:08:58
From: Johnny
Subject: Re: Stove top espresso

<byronsspam@gmail.com > wrote in message
news:1188081303.959723.154720@z24g2000prh.googlegroups.com...
> I found a VeV Vigano stove top espresso maker at the Salvation Army
> and have been doing some experimenting with it. It is about 5 inches
> tall, make of stainless steel with brass handle, and makes a single
> shot of espresso. I saw the steam escape valve working today so I am
> happy that I won't be grenading myself in the attempt to make a
> coffee. One of the problems however, is that the product is not very
> hot when it is ready. Could a new seal improve how hot the espresso
> gets? The seal seems okay but this is an old device, looks like at
> least 30 years old. I have been making coffees by adding hot water to
> the shot of espresso, which I must say, tastes phenomenal.
> Any info or tips greatly appreciated.
>
>
> Byron
>
It is surprising how low a temperature will push the water up through the
grounds on the type of mocha pot you have. So if you start with cold water
you could very easily end up with luke warm coffee.
If steam is coming from the safety valve then there is still some sealing
left in the main gasket else you wouldn't build a steam head enough to
escape through the valve.
OTOH if you start with water that is too hot you won't be able to hold the
pieces without gloves in order to put them together.
IMO if you want the end brew hotter, start with the hottest water you can
handle when initially assembling the unit. That way the initial water going
through the grounds will be much hotter which is what is wanted.

It is very difficult to push water that is too hot through the coffee in
this type of mocha pot as the pressure required to push the water up the
tube, through the cofee and up the next tube is so low.

Whe water is boiling its saturated vapor pressure is one atmosphere. One
atmosphere in water column is about 34 feet and for the mocha pot the water
only needs to be raised up 5 inches or so which requires a meager 0.18 psi
or so to do. The saturated vapor pressure of water at 100 F is already up
around 1 psi, and if ambient is say 70F then the SVP difference is already >
0.5 psi, more than enough to push the water up through the grounds. So what
happens usually in a mocha pot is low temperature water gets pushed up
throuigh the grounds initially and may end up in the top at temperatures as
low as 100 F which as you note is way cooler than you want.
At the point when it splutters up top, there's no more water coming up as
the lower chamber water level is now below the tube of the filter, so any
further heat will just force steam through the grounds. When you start from
cold water the sputtering usually happens well after all the water that will
rise has risen.
Experiment starting with hotter water, see what difference it makes and
report back.
Here's a link showing several Viganos:
http://www.fantes.com/espresso_stovetop.htm






 
Date: 02 Sep 2007 19:53:37
From: =?ISO-8859-1?Q?Mats_Leid=F6?=
Subject: Re: Stove top espresso
In my experience it is the other way around; coffee gets too hot in moka
pots. I have a large Vev and a smaller Bialetti Brikka. Perhaps the
small s/s moka pots are having these problems?
I doubt a new gasket would change things for you though. The gasket is
only good for sealing the upper and lower half so you save all that
lovely pressure inside it when heating the water. The pressure gets your
water up through the coffee filter and into the top half. A leaky gasket
will let steam out, but the water that makes it to the top will be as
hot. It might taste burnt though, since the coffee will have been in
contact with steam and hot water for a longer time. Not so nice.

Since stainless is slower to heat up, perhaps you could help things by
pre-heating the top half by pouring some boiling water into it and let
it sit there until the water in the bottom starts boiling (which you
should be able to hear), and then quickly pour the water out, just
before the coffee starts oozing out into the top half?

HTH, good luck.

/zix

--
TMC - the European coffee forum
http://www.toomuchcoffee.com