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Coffee lore or myth?: Crema and pressurized baskets

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Lore:

Quote

...a pressurised basket pushes the coffee liquid highly pressurised through a tiny hole. This is not crema. It's "fake" crema. Call it "foam" if you want....

I think this is myth.

Let me explain.

I've seen this said so many times across the internet and it's got me pondering what is actually meant.

The last sentence is key. I think people consider that the action of spraying action of pushing the coffee through a small hole creates the crema, similar to how spraying a high pressure jet of water at a hard surface can bubble up the water.

But, there are perhaps a few misconceptions with what is going on here.

Some thoughts:

1) Pushing fluid at high pressure through a small orifice (ignoring secondary effects) doesn't itself produce foam. It's the action of mixing with air as it hits a hard surface that makes the bubbles. 

2)The pressurised baskets have "crema pins". effectively, devices to slow down and dampen the output from the pressure baskets. This is in direct conflict with those who claim point 1 is at work.

 

3) There might be some depression gassing going on as water boils off as it's depressurised but I can't see this being a primary factor in crema here either. The water is below boiling point during the brew anyways and boiler pressures are low at brew temps. 

4) That the crema process is totally different in the pressurised and unpressurized baskets and this is why the espresso is different when doing either.

 

My current understanding is that it's the pressure that creates the Crema, nothing else. Anecdotal evidence suggests that as brew pressure is dropped, so does the Crema.

Crema is CO2 (or is understood to be) which dissolves into water under pressure and then regasses as the espresso leaves the basket to form the bubbles in the espresso.

This process is identical in both baskets, in fact, you could argue that the pressure profile through the puck is actually better for crema in the pressurised basket as pressure does not drop off through the basket as it does with unpressurized baskets.

So if the Crema is as good as or actually better when using pressurised baskets, why should taste be different in the cup? Well, the flow path and process is perhaps better in the pressurised baskets as water is pushed through the coffee, rather than pressed into it with the pressurised baskets.

Conclusion:

Crema, is really, the same with either baskets. Perhaps more so with pressurised baskets.

Taste is different because the actual extraction process is different.

 

Thoughts and criticisms plz.

 

 

Edit:

As described here:

https://youtu.be/j5rygXblZJU

 

Edited by Blue_Cafe

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