BREWHA Equipment Co Ltd. BIAC, User Manual

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needs to be 40°C/76°F in order to raise the total 10°C/19°F. Calculations need to be made to
determine the temperature of the recirculating water and the time to raise the temperature.
(Grain is a fairly efficient insulator, so heat under the Colander will not heat the grain bed
up—there needs to be circulation.)
To raise the temperature of the mash quickly, a technique similar to decoction mashing
should be used, in which the pump should be turned off and the water in the cone below
the Colander raised to the calculated temperature (to a maximum of 95°C/200°F). Then
the pump is started again and the heated wort circulated up into the Colander where it will
raise the temperature of the mash. If the calculations for a given temperature rise require a
volume greater than the cone volume (see Table E for cone volumes), two steps are needed:
first, the temperature below the cone is kept at the target temperature until the volume
recirculated AND the volume in the cone equals the calculated volume then the temperature
is set to the new step temperature while recirculation (to empty out the hotter wort in the
cone) continues. (A maximum temperature
of 95°C/200°F is recommended, as heating
any higher will likely cause foaming up the
sides of the Colander —if this starts to occur,
lower your maximum temperature.)
Fortunately (unless you love math) Beersmith
has a decoction calculator that gives the
amount of water needing to be recirculated.
In the Beersmith example shown in Table F,
with a temperature rise from 55C to 65C, a
strike volume of 575L (100L in the cone and
475L in the Colander) and 300lb of grain, the
calculator indicates that 175L are required.
To achieve this, with the pump off, heat the
area below the Colander to 95°C. Then start
the pump and circulate for 7.5 minutes
at 10L/min, keeping the wort in the cone
at 95°C. At this point, one will have put 75L of 95°C water/wort into the Colander, and there
will still be 100L of 95°C water below the Colander for a total of 175L of water. Then set
the ETC back to a target temperature of 65°C and continue recirculating. The temperature
in the cone will gradually drop as the wort from above cools it, and the temperature in
the Colander will rise. After 20–30 minutes the mash should be very close to the target
temperature. (As with decoction mashing, it is important to keep the mash pH at the low end
of normal—close to 5.2—in order to minimize any tannin extraction.)
Check the mash pH to ensure it is around 5.1–5.3. If it is higher or lower, adjustments may
need to be made early in the mash. There are several ways to adjust pH, but one is to add
a small amount of sodium bicarbonate (baking soda) to raise the pH if too low, or a small
amount of calcium sulfate (gypsum) or acid (lactic or phosphoric) if the pH is too high. Water
chemistry can be complex and varies from region to region, so refer to literature on the
BIAC User Manual Brewing
Table F