Slick BricksIf the mortar retains too much water the bricks tend to float on the mortar bed, which makes it difficult to lay plumb walls at a reasonable rate. In either case there will be poor bond.
The power of a brick to absorb water is measured by the initial rate of absorption.
Low suction bricks need a leaner mortar to give good bond. Usually this is done by increasing the proportion of washed sand in the mix.
High suction bricks require a mortar with very high water retention, making it necessary to shorten the length of the bed joint or wet the bricks to reduce their suction. It should be noted however that wetting the bricks can lead to efflorescence in the brickwork.