Cider production: cask conditioned cider: undrinkable sediment in practice
Cider makers should have a regular programme for monitoring undrinkable sediment levels in cask conditioned ciders to ensure that actual sediment volumes are consistent with those he has notified to his customers on invoices, delivery notes or price lists. Cider makers are required to make clear the dutiable volume in each container to their customers. Further information can be found in paragraphs 8.3.5 to 8.3.7 of Notice 162 (GOV.UK).
It is not acceptable to base undrinkable sediment allowances on the volumes of cider returned to cider makers in casks from the trade. The containers have left the cider makers’ control and the integrity of the cider returned is uncertain.
If the cider maker is using the most common method for establishing undrinkable sediment volumes, do not agree a percentage figure across the various qualities and container sizes. The agreed undrinkable sediment figures should be in pints or litres for each container size and type of cider produced. If the cider maker chooses to use a laboratory method to measure undrinkable sediment, there may be a common percentage figure across container sizes.
Sediment levels should be regularly monitored by cider makers and reviewed and amended at least annually. HM Revenue & Customs (HMRC) must be notified of sediment levels.
The BEER guidance has a section on the background to/requirements of the concession as it applies to the beer industry which you may find helpful - BEER18060 refers.