It tastes different from the last tub

Customers detect flavor changes readily and report them confidently. The useful work is separating the two quite different things they might be describing.

Two very different causes

The blend has separated within the tub, so the flavor changes as the customer works down it. Or the batch differs from the last one, so their new tub does not match their old one.

The first is a mechanical failure and a potency risk. The second is a control failure. They need different investigations and customers describe them identically.

Segregation within one tub

Flavor systems and high-intensity sweeteners are small components with particle sizes and densities unlike the bulk, which makes them the first things to separate.

The signature is a customer saying the first servings were sweeter, or the last were bland. That is the flavor component sitting at one end of the tub, and if flavor has segregated then anything else small has too, including actives.

So a flavor complaint is a potency warning, and it should be investigated as one.

Drift between batches

A new lot of flavor system, a new supplier, a changed grade, or a process change: a different blender, a different blend time, a different batch size.

Raw material variation is the usual culprit and it is invisible on receipt, because the certificate says the material meets specification and specifications rarely cover the sensory profile.

Finding which it is

Sample from the top, middle and bottom of a retained tub from that batch and taste them against each other. If they differ, it is segregation. If they match each other and differ from the previous batch's retained sample, it is drift.

That is a ten-minute test and it needs retained samples to exist, which is the argument for keeping them from every batch rather than occasionally.

References