Quote Originally Posted by 325abn View Post
What is filter aide made from and how does it not add "stuff" to the syrup?
"Filter aid" is diatomaceous earth (DE), or fossil diatoms (small ocean creatures). Their shells are made of silica, which is inert (so it doesn't add anything chemically or physically to the finished syrup). With a pressure press (plate or cannister), you have papers in the filter, but it is the DE that provides the filtering surface. The DE builds up on the paper, and requires the syrup to pass through the layer of DE and through the paper. Such pressure filtering is used widely in the liquid food and beverage industries.