Should I Keep a Small Retained Sample From Every Fragrance Batch so I Can Compare Future Deliveries and Investigate Customer Complaints?

What a fragrance retain is for

A retained sample has two jobs. The first is comparison: when the next delivery of the same oil arrives, you compare it against the oil you last approved, rather than against a recollection. The second is investigation: when a customer says a candle smelled wrong, weak or different, you can go back to the oil that went into it and check whether the material itself contributed.

Both jobs depend on the retain still being close to what you received. That is the difficulty with fragrance oil. Unlike a block of wax, it is a mixture of volatile materials, and every time it meets air, some of the lightest escape and some oxygen gets in. A retain kept carelessly becomes a record of how the oil aged on your shelf, which is a different thing entirely.

This matters more for fragrance than for most candle materials because CSI, like many suppliers, does not publish lot numbers, certificates of analysis or per-lot specifications for its oils, and its pages describe no retained samples kept on your behalf. If you want a reference for a batch, you have to keep it yourself.

Container, fill level and headspace

The container and how full it is do most of the work. Air in the vial is the enemy, so the smaller the gap above the oil, the slower the change. A 10 g vial filled nearly to the neck will keep far better than 10 g sitting in the bottom of a 100 g bottle.

Do not use the production container itself as your retain. You will keep opening it, its headspace will grow as you use it, and by the time you want to compare, the last of the oil will be the most aged part of the batch.

Where to keep it and for how long

Store retains cool, dark and at a stable temperature. A closed box in a cupboard away from windows, outside walls and production heat is usually enough. Keep them apart from open fragrance and from wax melting areas, and group them by oil so you can find the right one quickly. Avoid places where temperature swings daily, because repeated warming and cooling is harder on an oil than steady conditions.

For the retention period, work from your own products rather than a borrowed number. A sensible rule is to keep a retain at least as long as candles made from that batch are likely to be in customers' hands, plus a margin. If your candles usually sell within a few months and are burned within a year, keeping the retain for a similar period after the last candle from that batch was sold is a reasonable suggested starting point. Write the rule down, apply it to every oil, and note the disposal date on each label when you retain it.

Keep a log of openings

Put a short tally on the label of vial A each time it is opened. A working vial that has been opened twice is still a good reference; one opened fifteen times is starting to tell you more about your comparison habits than about the batch. When the tally gets long, decant a fresh working vial from the next delivery and demote the old one to test use. Vial B should have an empty tally until the day it is needed.

It also helps to keep a brief strip note with each retain, written on the day of goods-in: two or three words on the opening, heart and dry-down. Months later, when you open vial B, you will be comparing it against both the oil and your own description from the day it arrived, which makes it easier to judge whether any change is in the vial or in your nose.

Worked example: cost and space for a year of retains

Take Jasmine at ₹3,923.00 per kilogram, which is ₹3,923.00 ÷ 1,000 = ₹3.923 per gram. A split retain of two 10 g vials uses 20 g, worth 20 × ₹3.923 = ₹78.46. At 8% of a 200 g candle, 16 g fills one candle, so the retain costs a little more than one candle's worth of oil.

Now scale it. A small business that receives twelve fragrance deliveries a year, all of them Jasmine for the sake of the arithmetic, would retain 12 × 20 g = 240 g of oil, worth 12 × ₹78.46 = ₹941.52 across the year. In real life the oils will vary and so will the figure, but the order of magnitude holds: retains cost a small fraction of the oil you buy. Space is even less of an issue. Twenty-four small vials fit in a shoebox.

Jasmine is a useful example for another reason. Its page lists 0% vanillin and a flashpoint of 185°C, so it is not an oil expected to darken wax through vanillin. If a retained vial of it darkens noticeably over months, that tells you something about your storage conditions, and it is worth checking the other vials in the same box.

Labelling and the record that links it to candles

A retain nobody can identify is just an unlabelled bottle. Label each vial so that someone who has never worked in your workshop could trace it, and keep a matching line in your records.

The candle batch row is what turns a retain into an investigation tool. Each time you pour from a container, add the candle batch code to the record for that container's retain. When a complaint arrives with a batch code on the candle, you can go straight to the matching vial B.

Be prepared for the result to point at you rather than the oil. A retain that matches current stock and makes a good candle suggests the cause lies in the recipe, the process or how the candle was used. That is still a useful answer, and it is honest to act on it rather than assume the supplier was at fault, whoever that supplier is, including us.

Where this page fits

CSI already has guides that cover parts of this question. This page covers the goods-in check for the question above; these go deeper on the rest:

Three things to buy for this job

Frequently asked questions