The term 'CERTAIN SAUCE SOURCE' can be solved by the crossword solutions CARAMELS (8 letters) and SOY (3 letters). CARAMELS are a type of confectionery made from sugar, butter, and milk. They are usually soft and chewy and come in a variety of flavors. SOY is a type of legume that is widely used in Asian cuisine. It is often used as a source of protein and is also used to make sauces and other condiments. Both CARAMELS and SOY can be used as sources for certain sauces.