Important notes on sampling cream based samples on an AlcoTest.
The first point to think about is that the reference method for an alcohol measurement is distillation and measurement result from the density meter. This is the baseline that the instrument is compared with and the distilling of cream liquors is difficult. People do it, but if the customer distills 100 cream liquor samples and a 100 flavored vodka samples the baseline reproducibility, the cream liquor will be worse.
The AlcoTest is set up to measure alcohol, sugar and water. If you measure something that is just alcohol sugar water (for example raspberry vodka) the instrument will measure well and probably will not even need an offset.
Cream based materials are about as far from alcohol / sugar / water as a sample can get so it's going to need a huge offset compared to other samples. That offset is going to be proportional to the amount of cream in the sample. If the amount of cream is consistent then they can probably use the same offset from batch to batch.
Q&A
Question: Is an additional method needed for cream-based products?
Answer: The Alcotest can obviously measure cream liquors in reference mode. Distill the sample and use the regulatory method. The instrument is just functioning as a straight density meter, so the amount of time needed is the same as any other density meter. When you do this, you can also record the result in routine mode and see what the offset is.
Question: Are there any recommended instrument settings or sample preparation techniques?
Answer: Next time a sample is measured record the routine and regulatory results and see if the offset is the same. If it is similar to the last one, then probably that offset can be used for the rest of the batch.
In Conclusion:
- The alcotest can measure all samples.
- Many of the samples can be measured in the quick (routine) mode that eliminates the need for distillation
- Some of the samples can only be measured in the regulatory mode that requires distillation
- Cream samples are more likely to fall into the second category where distillation is necessary