A method of making a crystalline molecular sieve of MFS framework type, said method comprising the steps of (a) adding at least one source of ions of tetravalent element (Y), at least one source of ions of trivalent element (X), at least one hydroxide source (OH−), at least one structure-directing-agent (R), at least one seed source (Seed), and water (H2O) to form a mixture having the following mole composition (expressed in term of oxide): YO2:(n)X2O3:(x)OH−:(y)R:(z)H2O+(m)Seed wherein the m is in the range of from about 10 wtppm to about 2 wt. % (based on total weight of the synthesis mixture), the n is in the range of from about 0.005 to 0.05, the x is in the range of from about 0.01 to about 0.3, the y is in the range of from about 0.03 to about 2; and the z is in the range of from about 3 to about 30; and (b) treating said mixture under crystallization conditions to form said crystalline molecular sieve substantially free of non-MFS material, wherein said crystallization conditions comprise a temperature in the range of from about 150° C. to about 250° C., and crystallization time less than 100 hr, the weight hourly throughput is at least 0.001 hr−1.