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COOKER WHISTLES AT FULL OPERATING PRESSURE
4. Placing the Vent Weight
Once steam is coming out of the vent tube steadily, place the
vent weight on the vent tube and press down firmly. Keep fingers on
top of the vent weight and away from the steam when placing the
vent weight on the vent tube. A click indicates that the vent weight
is in position. In about 1 to 3 minutes, depending upon the size of
the cooker, it should come to full operating pressure – which will be
indicated by the first "whistle".
5. How to Recognise Full Operating Pressure (FOP)
After the vent weight is placed on the vent tube, there is at
first a very low hissing sound of steam from the vent weight. This
is not FOP. Then steam emission increases to full force and the vent
weight lifts with a whistling sound. The pressure cooker is now at
FOP.
When cooking, FOP is the point at which to reduce the heat and
start timing the recipe.
6. Maintaining Pressure on Reduced Heat
Once full pressure is reached, reduce heat from HIGH to
MEDIUM or lower. When cooking, the correct heat setting to
maintain pressure on reduced heat will vary with the type and
quantity of food and also your stove. The pressure inside the
cooker will be maintained at 1 kgf/cm
2
or about 15 pounds per
square inch. If the cooker whistles too frequently (more than
4 whistles per minute), reduce the heat still further.
If there is no steam coming out of the vent weight for about
four minutes, increase the heat gradually until the steam comes out.
Please remember that, particularly on electric hot plates, it may
take some time for heat level adjustments to have an effect on the
frequency of whistles. A little practice will make clear the correct
heat setting and adjustments, if any, that may be required.