Both HLTs are heated up overnight to their required temperatures
. The water is recirculated from the bottom of each tank to the
top a number of times to ensure that there are no layers of uneven
temperature .
The
grain for the specific recipe is weighed out and tipped into the
grist case. Water from HLT 1 is then pumped into the mash tun to
pre-heat it. This is then run off into the kettle were it is used
for sanitising the vessel . Water is again added to the mash tun
until it covers the plates in the mash tun and is at a temperature
of 72 oC (the strike temperature)
An
auger is then turned on and the grain is lifted out of the grist
case and is wetted with water from HLT 1 (84-86 oC ) as it falls
into the mash tun. Enough water is used to produce a stiff mash
at 65oC when all the grain has been added. The mash is then left
for 90 minutes and the enzymes in the grain convert the starches
present into sugars.
The sugary wort is then run out of the mash tun into the kettle
. Hot water from HLT 2 ( 78-82 oC ) is used to flush out any sugars
held within the grain bed via a sparge arm. Once sufficient wort
of the correct gravity ( sugar content ) has been collected, the
run off is stopped and the boil is started.