Thanks Gurkan for contacting the WWCC, but thanks in particular to WWCC and staff for assisting all us traditionalists.
Bob, re your question... Calf rennet is more powerful (i.e. economical) than non-animal rennet. Although that would probably depend on the strength and supply/demand of the product (this is an argument I have seen in Europe). I am guessing the economical aspect will not be of use here due to the serious lack of supply versus high demand in our current situation. While it can be used in place of vegetable rennet for all cheeses, it is more at home in long ageing cheeses like a classic vintage cheddar style cheese. It ages far better. I have heard that veg rennet can produce a sour taste in the cheese if it is aged too long, where as traditional animal rennet does not. I am sure one of our 'mature cheeses' in the forum can elaborate from experience on this aspect of calf rennet better than I can. Gurkan? Comments? Veg/microbial rennet is used a lot (if not solely) these days to keep vegetarians happy. Sounds obvious that cheese is vegetarian (ova-lacto vegetarian - not vegan), but it is not strictly vego when calf rennet is used (even though it is just a drop or two). Anyway, those are my thoughts. I simply want to use calf rennet from a traditionalist point of view. There is probably less calf rennet in cheese than there is human DNA/hair/skin cells in vegetarian products that are hand made. Sorry... I am not anti-vegetarian - I am just not vegetarian.