Temperature study: Flair espresso maker

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naked-portafilter
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#1: Post by naked-portafilter »

Hi there,

I thought that it would be an interesting thread to discuss the temp behaviour of the Flair espresso maker (similarly to the Olympia Cremina Temperature Study, Part 4). After that thread, I was fed up pulling my shots with wires but 3 years have gone. I can suffer :-) a bit again.
We have a scrap custom piston for pressure measuring I thought I could use that one for such measurements.





To be continued...

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naked-portafilter (original poster)
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#2: Post by naked-portafilter (original poster) »



I will make 4 series of measures with different pre-heating procedures.

1. Filling the cylinder with boiling water one time

2. Filling the cylinder with boiling water twice

3. Filling the cylinder with boiling water three times

4. Pre-heating the cylinder in boiling water.

I will log the temps with the Artisan roast logger measuring the temperature on the surface of the cylinder and in the brewing chamber.

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naked-portafilter (original poster)
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#3: Post by naked-portafilter (original poster) »

1. Pre-heating the cylinder with boiling water once, dumping the water, placing the cylinder, filling the chamber with boiling water, starting the pull



Pull (cropped out):


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naked-portafilter (original poster)
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#4: Post by naked-portafilter (original poster) »

2. Pre-heating the cylinder with boiling water twice, dumping the water, placing the cylinder, filling the chamber with boiling water, starting the pull



pull



Video of the temperature profile:

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naked-portafilter (original poster)
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#5: Post by naked-portafilter (original poster) »

3. Pre-heating the cylinder with boiling water three times, dumping the water, placing the cylinder, filling the chamber with boiling water, starting the pull



pull


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naked-portafilter (original poster)
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#6: Post by naked-portafilter (original poster) »

Pre-heating in boiling water





pull:


issy
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#7: Post by issy »

How does the "moka-pot steamer" pre-heat method compare to those results?

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naked-portafilter (original poster)
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#8: Post by naked-portafilter (original poster) replying to issy »

I don't have any experience with the moka-pot pre-heat method. But the final the temperature of the cylinder depends most probably mainly on the pre-heating duration. I just tried to demonstrate the correlation between the temperature of the cylinder and the brewing water.

vit
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#9: Post by vit »

Gabor, thanks for these nice measurements

I was also measuring the temperature of the outside wall of the cylinder, but this info actually doesn't tell much about what is inside. Cylinder is thick so inner and outer surface are not at the same temperature due to limited conductivity of the steel

There are other things affecting brewing temperature besides duration of cylinder preheating (in case of boiling preheating). First, not all stoves are the same. Induction stove which I thought would be the best proved worst, because induction doesn't heat the center of the pot, so while water boils outside very quick, inside of the cylinder takes ages to preheat (silicone doesn't help here either). Hi light stove gave me better results and higher brewing temperatures despite lower power. I suppose strong electric kettle should be the best, because bottom plate is probably considerably above 100°C due to limited heat transfer from plate to water, so heat transfers to cylinder due to direct conduction as well. I suppose gas should be similar to induction

Once you take cylinder out, it cools also due to water evaporation on inner and outer surface (in addition to convection and radiation), before you pour the water. This is where I suppose to be the benefit of steam preheating (putting the cylinder on smaller moka pot, csezve or similar vessel with some water), because cylinder ends up less wet. Unfortunately, my temperature probe that I used for measuring cylinder temperature broke in the meantime, so I didn't make much measurements of it (while those that I made returned similar results like yours), but it looks like this method can give a bit higher brewing temperatures, as I'm getting satisfactory results with lighter roasts only this way. It would be nice if you could try measuring this as well

With steam preheat, it seems to be good idea to partially cover the top of the cylinder during preheating, so that it's only steam inside - preheating seems to be faster that way - and uncover it immediately before pouring the water into it

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naked-portafilter (original poster)
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#10: Post by naked-portafilter (original poster) »

vit wrote:Gabor, thanks for these nice measurements

I was also measuring the temperature of the outside wall of the cylinder, but this info actually doesn't tell much about what is inside.
Hi Vit,

I placed the second probe deep in the brewing chamber letting the screen push it back as the piston travels down at the end if the pull. It is a 1mm k-type thermocuple in a 1mm bore "sealed" with silicone. That way you can see the exact temperature in the inside (during the pull). Even more, you can see the correlation between the temperature of the cylinder and the brewing water. As I see all 4 methods offer a controllable way in amazingly short time to pull a decent espresso.

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