User Experience with the Strietman CT2 - Page 59

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Stevebcoffee
Posts: 63
Joined: 9 years ago

#581: Post by Stevebcoffee »

Haven't got a Strietman but had a Flair and Robot. Both had a gauge and I was initially surprised as to how much pressure I needed to apply to get the shot to start at 9 bar after preinfusion. Is this similar on the Strietman or are people pulling at lower pressures?. On the videos I've seen it doesn't seem to be much effort applied. Not that I think 9 is ideal though, I often pull 6 bar on the Decent

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Chrikelnel
Posts: 184
Joined: 5 years ago

#582: Post by Chrikelnel replying to Stevebcoffee »

I have a CT2 and a Robot, I think the Robot takes a bit more effort to get to 9 bars. I can get to 9 bars with the Strietman one handed easily, though I find 6-7 bars to be the most 'natural' level personally.

tompoland
Posts: 268
Joined: 3 years ago

#583: Post by tompoland »

The comparison between the CT2 and a Flair will depend on which model of the latter you are comparing the CT2 with.

I have a CT2 (49mm basket) and I've used a Flair Signature Pro (46mm basket I think) for travel. The CT2 seems to need a more weight on the lever, perhaps because of the curve in the Flair's lever? But there is not a lot in it.

I have a Flair 58 (58mm basket) and I suspect that will require less muscle than either the CT2 or Signature Pro because the basket is wider and shallower.
A little obsessed.

renatoa
Posts: 769
Joined: 7 years ago

#584: Post by renatoa »

Nope, pressure is not related to puck height, but to piston area.
One bar is 1 kg per square cm area. The areas for the baskets involved in this thread are below:
46mm = 16.6 ; 49mm = 18.9 ; 58mm = 26.4 kg/sqcm for one bar

Multiply by 6...9 to find the force on piston shaft to obtain the desired pressure.
Divide by lever ratio and you will find the force on handle, somewhere in the 10-15 kg ballpark for all levers I tested.

jley08
Posts: 35
Joined: 2 years ago

#585: Post by jley08 »

Does anyone have a good recipe in how to descale the CT2?
What type of acid did you use, etc.?

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truemagellen
Posts: 1219
Joined: 14 years ago

#586: Post by truemagellen replying to jley08 »

I use about 1 tablespoon of citric acid and enough distilled water to fill boiler (I usually premix it). Warm to about 130f. Then shut down let it sit for 20mins or less if it is a minor descale. Then just rinse it out 2 times with filtered water I typically use.

If there is grime or slime I will take it all apart and wipe clean with microfiber towel and then run the towel through and kind of scrub it top to bottom

Stevebcoffee
Posts: 63
Joined: 9 years ago

#587: Post by Stevebcoffee »

Gonna stop reading this thread now as my wallet has started to be become anxious. I have 6 machines and don't need another!

tompoland
Posts: 268
Joined: 3 years ago

#588: Post by tompoland replying to Stevebcoffee »

Yeah you do!
A little obsessed.

tompoland
Posts: 268
Joined: 3 years ago

#589: Post by tompoland »

renatoa wrote:Nope, pressure is not related to puck height, but to piston area.
One bar is 1 kg per square cm area. The areas for the baskets involved in this thread are below:
46mm = 16.6 ; 49mm = 18.9 ; 58mm = 26.4 kg/sqcm for one bar

Multiply by 6...9 to find the force on piston shaft to obtain the desired pressure.
Divide by lever ratio and you will find the force on handle, somewhere in the 10-15 kg ballpark for all levers I tested.
Thanks for that. I appreciate you taking the time to correct false conclusions.

It surprises me that surface area and depth don't have a bearing on the pressure required to extract a certain flow rate. I thought that a basket that was say 100mm wide and 1mm deep (extreme I know but testing the hypothesis) would require less pressure than a basket that was say 1mm wide and 100mm deep. But I can see now that my theory has as many holes in it as a portafilter basket and so I'll happily defer to your greater knowledge.

I was going on what my arm felt like but I appreciate that's very subjective and that there are also variable from one pull to another e.g. grind size, water temperature and more.

So have I got this right: if the grind weight of the coffee is the same, it really doesn't matter if there is a variance in depth/width of the puck, the pressure required to extract is going to be the same?

Thanks.
A little obsessed.

harris
Posts: 161
Joined: 17 years ago

#590: Post by harris »

Stevebcoffee wrote:Gonna stop reading this thread now as my wallet has started to be become anxious. I have 6 machines and don't need another!
Need became irrelevant after the second machine, dust off your wallet and jump in.

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