PRE-INFUSION FLOW RATE
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STÉPHANE RIBES –APRIL 2020
PRE-INFUSION FLOW RATE
TEST PROTOCOL
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•Decent Espresso Machine DE1PRO v1.1with a (red) Cafelat 8.0 mm silicone gasket
•IMS SI 200 IM screen (no spacer)
•Mahlkönig EK43 S grinder – SSP burrs “High Uniformity” with Silver Knight coating
•Montille water (Le Mont Dore, France) –adjusted to 50 ppm eq. CaCO3alkalinity and
125 ppm eq. CaCO3total hardness, with sodium carbonate and Epsom salts
•Portafilter pre-heating: 70°C in a kettle
•Complete drying of the basket and shower screen before each shot, with a clean tissue
•Single dosing of the beans, ground in a double walled stainless steel cup
•VST 15g ridgeless filter basket, brew ratio of 2.3
•WDT in the basket with a Londinium tool (and a Decent funnel) –no vertical tapping –gentle
raking of the coffee grounds with a hog tool, to obtain a uniform surface
•Hog puck preparation tool (thin pikes) in and out of the puck, with a stand to ensure a straight
vertical movement (picture)
•The Force Tamper with a 58.5 mm smooth flat base –used twice in a row
•TDS measurements: Atago PAL zeroed with adjusted Montille water –no filtering of the coffee
samples –all samples measured at room temperature after vigorous stirring
1 data point = average of 3 to 5 measurements of each coffee sample
HYBRID “LEVER-BLOOMING” PROFILE
2.5 ML/S EXTRACTION –85°C
•Combination of the Londinium and
blooming profiles
•The initial step “lock portafilter!”
is optional: it prevents exposure of
the coffee puck to the hot machine
environment during the final warm-
up of the brew water
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Pre-infusion flow rate: All shots: same grind size,13g in, 30g out –Total shot time: 33s
IMPACT OF THE PRE-INFUSION FLOW RATE
ON THE ESPRESSO EXTRACTION
2.4 mL/s 3.0 mL/s 4.0 mL/s 6.0 mL/s 8.0 mL/s
EY 19.5% EY 19.8% EY 20.0% EY 19.6% EY 19.9%
Pre-infusion flow rate: Coffee dose adapted to reach a pressure peak around 6 bar
IMPACT OF THE PRE-INFUSION FLOW RATE
ON THE ESPRESSO EXTRACTION
2.4 mL/s 3.0 mL/s 4.0 mL/s 6.0 mL/s 8.0 mL/s
EY 19.5% EY 19.5% EY 19.9% EY 20.0% EY 20.0%
+ 0.3g+ 0.3g - 0.3g - 0.3g