Temperature of water without portafilter

[TOK]

with only a little tweaking you could modify it to make coffee at the same time it's scasing....

[JavaBeanery]

Nar, by the time you build it it will be obsolete. I'd be looking at a scaseIIIa straight up. The IIIa will also have the advantage that with regular use the equipment its used with wont require descaling or retain grinds...best of all worlds




Hope so

Tok, Damit... would want to get a scace pf now....

Just cant live without getting geekier about it......

And another reason is that the pf just looks plain cool...

:drool: :drool:

[TOK]

...I think i would build a scace2 too, but where do we get the multimeter from.....

Nar, by the time you build it it will be obsolete. I'd be looking at a scaseIIIa straight up. The IIIa will also have the advantage that with regular use the equipment its used with wont require descaling or retain grinds...best of all worlds

.....
What's next in this crazy world ?
A mechanic with Eye Shadow n Lippy ?

Hope so

[TheLudicrousBean]

But doesn't the Scace2 also read pressure....

I think i would build a scace2 too, but where do we get the multimeter from.....

[EspressoAdventurer]

The machine maintenance guide on that site is very useful too....

Mal.

Re: Mal's qoute regarding the Gaggia Site ( maitenance) I thought I'd have a look over lunch - like ' do myself a favour' !

GAGGIA

So to all the pro's here - what gives ? An espresso machine repairer with Nail Polish !!

What's next in this crazy world ?
A mechanic with Eye Shadow n Lippy ?

[JavaBeanery]

1+ to the coffee machinist...

Although not a HX, it does arguably make a lot of sense

[coffee_machinist]

I think of it as a variable offset, so even on a supremely temp. stable machine, changes in flow rate will affect measured temps (Newton's law of cooling re. rate of change of brew water with respect to the temp of it's surroundings- once outside the group or group/boiler).

We know that water temp. inside saturated boilers (and mean temp inside HX tubes/group casting) is above our desired brew temperature, offsets of between a few degrees and 12 degrees are common. Thus desired extraction temp. as far as I am concerned is a function of internal water temp at source (maintaining temperature due to large thermal mass, and energy being put in) minus a variable offset dependent on how quickly energy is lost. If flow rate is higher, the water at source temp. is displacing the cooling volume in the basket/thermofilter more quickly.

[MrJack]

That is quite interesting. Makes you wonder what is really the variable of interest; temp into the puck or temp within it?

Does this observation differ between HX and double boiler machines at all?

[coffee_machinist]

Flow rate and measured temperature are intrinsically linked in a thermofilter. The Scace uses not a needle valve per se, it's a fixed restrictor jet and a sintered bronze filter. The plastic insert is thermally inert so as to not absorb heat energy away from the brew water, which is losing heat very quickly when it exits the group. Thus if you have a ristretto flow rate, your brew water is cooling in the puck or thermofilter and resulting temps read lower. Very easy to see if you can control the flow rate, as I do with my scace rip-offs for workshop use. I generally use flow rates quite a bit slower than the Scace gives. No numbers to quote, just an eyeball 'that looks like a shot I'd drink' flowrate.

[TheLudicrousBean]

Talk Coffee, Congratulations on getting a very expensive PF that championship baristas use......

How's your bank account?

[MrJack]

Where is the needle valve? The brass fitting?

I wonder if, rather than trying to replicate the properties of the puck, the plastic insert is actually to minimise heat transfer between the water and the device, and to direct water onto the thermocouple at as close as possible to the inlet temperature.

May also improve the response time, by increasing the flow velocity over the thermocouple.

[TC]

Pics of Scace II showing internal anatomy and needle valve

[MrJack]

The odd thing about that TC, is that surely you want to know what the temperature of the water is when it reaches the puck - not afterwards.

Replicate the flowrate certainly (you could just use a needle valve), thermal properties seems less useful.

[TC]

Hmm. I am not so sure about that Robbks.

A Scace attempts to replicate the flow of a shot in addition to the thermal absorption properties of the coffee puck. The Scace II delivers temperature and pressure readings as well.

[Robbks]

A "Scase" is just a PF with a thermocouple attached to it.
I built my own with an old unused single basket.

drilled a small hole in the of the basket just off centre
Attached the thermocouple securely with some conductive heatsink cement