A breakable capsule such as a seamless breakable capsule useful in a smoking article or a smokeless tobacco product includes an outer shell formed of a cross-linked agar matrix including at least one filler, and an inner core surrounded by the outer shell which comprises a liquid or gel based composition of a flavorant and/or non-flavorant. The cross-linked agar matrix is reinforced with carboxymethyl cellulose that is dispersed throughout the agar matrix so as to fill empty spaces in the agar matrix and inhibit the composition from passing through the empty spaces of the agar matrix.