A 33% lye solution is 2 parts liquids (water) to 1 part sodium hydroxide (lye). Like Smelli says, a stronger concentration means less water to evaporate. The default setting on SoapCalc is at @28% lye strength. The "38" default setting refers to 38% of oils weight to water usage, which is about a 28% solution strength. Hope I have not confused more. :?