Not profiling but setting the overall brew pressure on a non-paddle. When I first got involved, I believed 9bar was the "correct" setting. But in the past few months I've been playing with pressures and find that the coffee tastes much better (to me) at 7.5bar.
So my questions
What am I affecting running a lower pressure? For those of you that play with pressures, do you find certain pressures are better for certain coffees? How low can I go before I'm no longer making espresso?!! (more of a joke!)
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Joined: Thu May 05, 2005 1:16 am
Postby another_jim » Thu May 12, 2011 1:49 pm
As a very rough guide, the sweet spot for rotary pumps is 7 to 9 bar. The slower ramp of vibe pumps puts their sweet spot at 9 to 11 bar. But these ranges are also affected by the details of the brew head, particularly the gicleur size and any other flow capacitances or resistances that affect the initial pressure ramp up.
According to Illy labs, the flow rate rate through a puck peaks at 9 bar, and drops at both lower and higher pressures. This means that the classic 25 second shot for proper extraction happen at 9 bar, and that higher or lower pressures would require slower shots for proper extraction. This, rather than taste, may be the reason 9 bar is used as the nominal pressure for espresso.
At 7.5 bar you are probably getting very lever like espresso which tends to be lighter in body and crema but it brings out the floral and fruit in most blends. I run my elektra at 8.6 bars if I remember correctly. I would have to put the scace on it to measure again.
Joined: Wed Jul 21, 2010 8:26 am
Postby mitch236 » Fri May 13, 2011 1:14 pm
How much can I trust the built in pressure gauge? I recently replaced it so it is essentially new. I don't want to buy a Scace pressure device just to check!
Joined: Fri Apr 29, 2005 9:13 pm
Postby HB » Fri May 13, 2011 1:28 pm
Rather than focus on a specific number, try increasing/decreasing the brew pressure at least 2.0 bar, then decide if you prefer the taste/texture of the resulting espresso. Halve the difference between the previous/current setting and repeat until satisfied.
Joined: Tue Jun 27, 2006 4:53 pm
Postby cafeIKE » Fri May 13, 2011 1:30 pm
Scrounge an old PF, remove the spout, buy a gauge from eBay, valve and fittings from local ironmonger and voila :
All in, less than $20 and within a pound of the High Price Spread.
NOTE : Liquid filled is not required. Liquid filling damps vibration and lubricates the mechanism
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