I came up with a format that works for me. My lot numbers look like this:
LOT: CX120A, where "C" stands for container, and "X1" stands for the month it was produced. X = 0, so X1 is the month of January. "20" stands for the year, and the "A" suffix tells me this was the first batch poured on that day. This information refers me to my worksheet where I can review all the details of that batch. If a customer submits a complaint, I can look at my data and see whats going on. This also allows me to do long term, ongoing research on wax and wick combinations.
Example 2--- LOT: P1019B, where "P" stands for pillar candle. 10 is the month of October [Notice the "X" is gone] and 19 represents the year, 2019. Here the "B" suffix stands for the second batch produced on the day in question.
Example 3--- LOT: SX220C, where the prefix "S" stands for "Specialty", which is a catch-all term for any other type of candle. The format tells me that this candle was poured in February of 2020 and the "C" represents the third batch of all the different candles made on that date.
I add the lot number to my worksheet, the candle label, and I enter it into a production spreadsheet log that I created. This format is simple, uniform and consistent. It's not overly redundant, and it provides all the information I need to go back and review what I did.