Japanese Knotweed Differences

there is often significant variation from supplier to supplier Rob

its hard to know exactly what you are experiencing - but differences in taste are not necessarily an issue as such - they may simply grow a slightly different herb strain, on different soil or harvest or process slightly differently - so its quite common to see some differences in colour texture or taste from batch to batch - even from the same supplier.

that said knotweed has a quite distinctive taste - kinda woody and bitter, drying of the mouth and tastes almost like its slightly burnt. when powdered it should be a pretty bright yellow-brown colour, which turns reddish brown when mixed with water.

some variation is to be expected - but i would say if its a very different colour - or the product smells or tastes completely wrong vs what you are used to - or smells strongly of something foreign like chemicals or mold - you may want to avoid it just to be on the safe side.

hard to be of much help remotely - but i hope its at least a little helpful