if you're down for modding anyway, there is a way to process blood into a lignate pot...well, I've only tested it in barrels, but it should work for pots too. I cant find the thread right now, I'll find it. What I did is add this:
[MATERIAL_REACTION_PRODUCT:EXTRACT_BLOOD:LOCAL_CREATURE_MAT:BLOOD]
to the meat template in material_template_default and add this:
[REACTION:PRESS_MEAT]
[NAME:press blood from meat]
[BUILDING:SCREW_PRESS:CUSTOM_T]
[REAGENT:meat:1:MEAT:NONE:NONE:NONE] [HAS_MATERIAL_REACTION_PRODUCT:EXTRACT_BLOOD]
[REAGENT:barrel:1:BARREL:NONE:NONE:NONE]
[EMPTY]
[PRESERVE_REAGENT]
[DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[PRODUCT:100:3:LIQUID_MISC:NONE:GET_MATERIAL_FROM_REAGENT:meat:EXTRACT_BLOOD]
[PRODUCT_TO_CONTAINER:barrel]
[SKILL:BREWING]
to the reaction_other file and add PRESS_MEAT to permitted reactions for the civ. the result is the same as the barrels of blood you can take with you on embark/trade for, but be warned it doesn't work well with ichor. In your case, you'd have to change the [REAGENT:barrel:1:BARREL:NONE:NONE:NONE] to whatever the reagent is for pots, which I haven't used yet so you'll have to find that out for yourself. The wiki should have it, maybe I'll look it up later. You'd probably have to gen a new world, too, which may or may not be worth the trouble.
Edit: Come to think of it, you'd probably also have to allow butchering of sentients, unless animal blood works just as well as dwarf blood.