It is inconsistent batch to batch

The raw material moves

Growing conditions, harvest timing, drying and storage all change what is in a botanical, and two lots of the same correctly identified species are not identical. That is normal and it is not an excuse, because your specification says what the finished product must be.

Which is what a specification is for

Setting a target for the finished product and adjusting the process to meet it, rather than running a fixed process and accepting what comes out, is the difference between a manufactured product and a batch of something.

Record the lot against the batch

Without it, a change caused by the material is indistinguishable from a change caused by the process, and you will spend a month adjusting something that was not the problem.

Extraction time and ratio drift

If the process is defined by a time and a ratio, every departure moves the product. Writing them down and holding them is the cheapest consistency work available, and the one most often left to judgment.

Taste and color are not the specification

They are the signals you notice, and a botanical product can look and taste different while being within specification, or match while being outside it. Judging by eye is reassuring and it is not the control.

Keep a reference

A retained sample from a batch that was right, compared against new work. Drift is invisible batch to batch and obvious against something from six months ago, which is the same discipline this library arrives at everywhere.

Decide what you do with an out-of-spec batch, in advance

Reworking, blending or rejecting are all legitimate and they have to be decided by a written procedure rather than in the moment by somebody looking at the cost of the material. That is what the deviation handling in cGMP is for.

References