HIGHER EXTRACTION FLOW RATES

WITHOUT CHANNELING?

STÉPHANE RIBES – FEBRUARY 2020

HYBRID “LEVER-BLOOMING” PROFILE – DECENT ESPRESSO DE1 PRO V1.1

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• With a higher final extraction flow rate but the same

coffee dose, a coarser grind will be necessary to stay

in the same range of extraction pressure. Consequently,

the target pressure of step 2 “pressurized bloom”

can be reduced, in order to avoid too much drippage

before the actual extraction phase

• During our tests, we found that a gentler increase in

flow rate (step 3) was necessary to avoid sour shots,

presumably limiting the extent of puck channeling

HIGHER FLOW RATES WITHOUT CHANNELING?

ADAPTATIONS TO THE “LEVER-BLOOMING” PROFILE

1.5 mL/s 2.5 mL/s

• Preinfusion – 4 mL/s – ends when 80% of the target

pressure of step 2 is reached

• “Pressurized bloom” (pressure priority step)

• Smooth transition to reach the targeted flow rate of the

final extraction stage

• Flow priority extraction with stop at weight (BR: 1:2.4)

• Optional initial step “lock portafilter” to prevent

exposure of the puck to the hot machine environment

during the final warm-up of the brew water

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Pressurized bloom: 10 sec – Flow rate increase: 4 sec 13g in, 31g out – 31s to 35s shots

Pressurized bloom: 4 sec – Flow rate increase: 10 sec 13g in, 31g out – 29s to 32s shots

2.5 ML/S EXTRACTION – IMPACT OF THE RATE OF

FLOW RISE DURING THE DIALING IN PROCESS

EK2.6Gs EK2.4 EK2.2 EK2.1 EK2.0

EY 19.9% EY 19.7% EY 19.6% EY 19.5% EY 19.4%

EY 19.8% EY 19.7% EY 19.9% EY 19.8% EY 19.4%

Pressurized bloom: 12 sec – Flow rate increase: 4 sec 14g in, 34g out – 42s to 45s shots

Pressurized bloom: 4 sec – Flow rate increase: 12 sec 14g in, 34g out – 40s to 44s shots

1.5 ML/S EXTRACTION – IMPACT OF THE RATE OF

FLOW RISE DURING THE DIALING IN PROCESS

EK2.3Gs EK2.2 EK2.1 EK2.03 EK1.95

EY 19.6% EY 19.5% EY 19.7% EY 19.4% EY 19.5%

EY 20.1% EY 19.8% EY 19.6% EY 19.6% EY 19.5%

HIGHER FLOW RATES WITHOUT CHANNELING?

TEST PROTOCOL

• Decent Espresso Machine DE1PRO v1.1 with 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. CaCO

alkalinity and

125 ppm eq. CaCO

total hardness, with sodium carbonate and Epsom salts

• Complete drying of the basket and shower screen before each shot, with a clean tissue

• Single dosing of frozen beans ground in a double walled stainless steel cup

• VST 15g ridgeless filter baskets

• 13g (2.5 mL/s extractions) or 14g (1.5 mL/s) of ground coffee – brew ratio: 2.4

• 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 (right picture →)

• The Force Tamper with a 58.35 mm US curved smooth 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

• Combination of the Londinium and

blooming profiles

• The initial step “lock portafilter!”

is optional: it prevents exposure of

the puck to the hot machine

environment during the final warm-

up of the brew water