GRINDING FROZEN BEANS FOR
ESPRESSO
MORE CONSISTENT EXTRACTIONS –MORE RESISTANCE TO WATER FLOW
FREEZING X WEEKS POST ROAST GIVES THE BEST TASTE RESULTS!
1
STÉPHANE RIBES –JULY 2019
Frozen 07/07 (6 days post roast)
GRINDING FROZEN BEANS FOR ESPRESSO
MORE CONSISTENT EXTRACTIONS
15/07 18/07
20/0719/07
•Same grind setting, extraction
parameters and workflow every
day (1 single shot/day with these
parameters)
•Friedhats Coffee Roasters –
Kochere Boji (natural Yirgacheffe) –
Roasting 01/07 (filter roast) –
Frozen 07/07 –18.5g dose in a
22g VST basket
•Limited variations in extraction
pressure and extraction yield
→lower need for dialing in once a
tasty recipe has been established!
2
EY 21.3% EY 21.4%
EY 22.0% EY 21.8%
No freezingFrozen 22/07 (6 days post roast)
GRINDING FROZEN BEANS FOR ESPRESSO
MORE RESISTANCE TO WATER FLOW
Shot #1 Shot #2
•2 shots performed in a row (27/07)
with unchanged settings
•Terres de Café –Chania Estate
French Mission (natural Kenyan) –
Roasting 16/07 (filter roast) –
14g dose in a 15g VST basket
•With frozen beans a coarser grind
is sufficient to reach a given
extraction pressure
→limitations of some grinders will
arise later (e.g. poor grind quality
when very fine grind is used)
3
Frozen 28/07 (+12 days)Frozen 22/07 (6 days post roast)
GRINDING FROZEN BEANS FOR ESPRESSO
IMPACT OF THE RESTING TIME BEFORE FREEZING (1/2)
Shot #1 Shot #2
Shot #3Shot #4
•4 shots performed in a row (29/07)
with unchanged settings
•Terres de Café –Chania Estate
French Mission (natural Kenyan) –
Roasting 16/07 (filter roast) –
14g dose in a 15g VST basket
•Lower extraction pressure peak with
6 additional resting days after
roasting
•Higher extraction yield
•More (pleasant) acidity
4
EY 22.6% EY 23.5%
EY 22.7% EY 23.7%
Frozen 28/07 (+13 days)Frozen 22/07 (7 days post roast)
GRINDING FROZEN BEANS FOR ESPRESSO
IMPACT OF THE RESTING TIME BEFORE FREEZING (2/2)
Shot #1 Shot #2
Shot #3Shot #4
•4 shots performed in a row (30/07)
with unchanged settings
•Terres de Café –Guji Highland Bio
(natural Ethiopian) –
Roasting 15/07 (filter roast) –
14.5g dose in a 15g VST basket
•Slightly lower extraction pressure
peak with 6 additional resting days
after roasting
•Slightly higher extraction yield
•More tasty, sweeter shots
5
EY 22.3% EY 22.6%
EY 22.2% EY 22.6%
GRINDING FROZEN BEANS FOR ESPRESSO
DETAILED TEST PROCEDURE
6
•Decent Espresso Machine DE1PRO v1.1 with IMS SI 200 IM shower screen
•Mahlkönig EK43 S grinder
•Montille water (Le Mont Dore, France) –adjusted to SCAA with sodium carbonate and
Epsom salts
•Beans were ground in a double wall stainless steel cup
•WDT in the cup with a mini whisk
•55 mm diameter Camlab paper filter below the coffee grinds –no preliminary wetting of
the filter
•WDT in the basket with a mini whisk –gentle raking of the puck surface with the hog –
no taps
•Hog tool 0.8 mm diameter spikes (“thin” Hog) in and out of the puck (with hog stand
to ensure a straight vertical movement)
•Manual tamp with a 58.6 mm diameter tamper
•TDS measurements: Atago PAL zeroed with SCAA water –no additional filtering of the
coffee samples –all samples measured at room temperature after thorough agitation –
1 data point = average of 3 or 4 measurements of each coffee sample
