I have 300L, 500L and 750L Roasted Barley so I created custom fermentables for them so could distinguish which one I am using in a recipe. Problem is if I include say 1 lb of the 500L in a recipe the pH suddenly drops to about 2.6. If I use the built in 550L UK Roasted Barley the pH is a more believable 5.5. I have ppg set to 29 and the mashed checkbox checked. Am I doing something wrong here or is there a problem?