A target given as two conditions: keep calcium above a floor, and hit a
sulfate:chloride ratio.
A brewer who says "at least 50 ppm calcium and a 2:1 sulfate to chloride"
has set two conditions and left the other four ions alone. That's a
different kind of target from a six-ion profile, and it's why a rule can be
satisfied exactly instead of fitted.
A target given as two conditions: keep calcium above a floor, and hit a sulfate:chloride ratio.
A brewer who says "at least 50 ppm calcium and a 2:1 sulfate to chloride" has set two conditions and left the other four ions alone. That's a different kind of target from a six-ion profile, and it's why a rule can be satisfied exactly instead of fitted.