It’s very frustrating. I usually just assume if it doesn’t specify, it is insoluble. Is this usually a safe bet?
With current labeling requirements, companies are not required to specify soluble vs. insoluble fiber. Only total fiber is required.
And you cannot assume that all fiber is insoluble if not specified. There are plenty of products that contain soluble fiber which only have total fiber listed on the nutrition label. Your best bet would be to look at the ingredients list and try to identify what the main sources of fiber are, and then look up those specific food items to see if they are considered soluble or insoluble.