Here’s the reply I got from Todd at Pacific Pectin regarding HM-100 set times:
“ The pectin used in our HM100 blend is extra slow set with a DE at about 60%. The Rapid setting can be caused by a couple of things. First is cooking temperature, the product will begin to set based on temperature and PH so if the cooking temperature is close to setting temperature the gel will appear to happen rapidly specially once the gummy has been poured and is segregated from the bulk heat of the batch. Pouring at a higher temperature can help give you more time to handle the product before it reaches that setting temperature (you might see presetting if you are handling the product around 190*F). Final PH is the next reason this product will gel quickly, target final PH is 3.5 at 75-80 brix. If the final PH is low the pectin will set extremely fast at the setting temperature, if the PH is spot on at 3.5 you should have a moment or two before the batch gets thicker and plugs up piston fillers. If the PH is too high you will get a smooth pour and a gummy that appears to be gelling but never gets passed the tacky state and wont hold its shape. If that’s the case add more citric acid, if you are low on PH reduce the added citric acid at the end of the recipe.”