Booklet “Welcome to Club Oracle™”

Water temperature
The World Barista Championship
requirements dictate machines used
in competition have temperature
stability of +/- 1.5˚C. Movements
beyond this can aect flavour
dramatically. In our testing, we
have never found a domestic
machine that comes close to
meeting this standard, other
than the Stollar Oracle™ and
the Stollar Dual Boiler™.
This has been achieved
using our innovative
triple heat system that
precisely controls water
temperature to +/- 1˚C.
Pre-Infusion
Just like the best commercial machines, the
Oracle™ gradually increases water pressure at the
start of the extraction to gently expand grinds
before applying higher pressure.
Without this gradual increase in water pressure,
“Channelling” or “Drilling” can occur. This means
water will pass between the tamped coee and the
wall of the basket or “drill” through the centre of
the coee and not the perimeter. This results in
bitter, over extracted flavours dominating the cup
as excess water passes through the “channel” and
not evenly through the entire coee puck.
Pressure
Maximum flavour potential is achieved when
espresso is extracted between 8-10 bars of
pressure. When too much pressure is used
bitter flavours dominate the cup. When too little
pressure is used a thin crema results leading to
poor mouthfeel. The Oracle™ and the Dual Boiler™
are among the very few domestic machines to
control this critical element.
Steam Boiler
Heated
Group Head
Espresso
Boiler
Low Pressure
Pre-Infusion
Evenly soaks
to expand grinds
No Pre-Infusion
Water drills through
the grinds
Even extracon across
the puck
Water burst through
causing under extracon