Most terpene "specs" are a strain name and a volume. That is a purchase order, not a specification, and it is the reason so many batch disputes end in two people describing smells at each other.
A real specification is a document that lets both sides answer one question without arguing: is this lot acceptable, yes or no. Everything below exists to make that question answerable.
What a specification has to contain
The compound list, with targets. Not "myrcene dominant". The actual compounds you are buying and the concentration each should land at. If the profile is proprietary and the supplier will not itemize it, you need at minimum the compounds that define its character and their targets.
A tolerance on each one. This is the part almost everyone omits, and it is the part that decides every future dispute. A target with no tolerance is not a specification, because any deviation is simultaneously acceptable and unacceptable depending on who is speaking.
The analytical method. Two labs running different methods on the same material can return meaningfully different numbers. If the spec does not name the method, "in spec" means different things to you and your supplier.
Appearance, and any physical limits that matter. Color, clarity, and for anything going into a cartridge, viscosity at a stated temperature.
What happens on a fail. Not the commercial consequence, just the process. Who retests, against which retain, and inside what window.
Tolerances, and why they are the whole document
Here is the thing nobody tells you at the start: a tolerance that is too tight is as bad as no tolerance at all.
Botanical feedstock varies. The same cultivar grown in two seasons produces different ratios, and a supplier formulating to a specification is compensating for that variation every time they blend. If you write a tolerance so narrow that honest material fails it, you have not bought quality, you have bought a monthly argument and a supplier who quietly starts rounding.
Tolerances should be tight on the compounds that carry the character and looser on the ones that do not. A profile whose identity sits in three compounds does not need the same rigor on the fourteenth.
The way to set them is empirically, not by picking a number that sounds rigorous. Buy three lots, measure them, see how much honest variation looks like, then write a tolerance that contains it with a margin. Our guide on why flavor drifts between runs covers where that variation comes from, which is worth understanding before you decide how much of it to permit.
Retains: the part that settles arguments
A retain is a sealed sample of the exact lot you shipped, kept by both sides.
Without retains, a batch dispute is two parties reasoning about material that no longer exists in its original state. The customer has product that has been through their process. The supplier has a number on a certificate. Neither can test the thing actually in question.
With retains, it is a lab question. Pull both, run them, compare against the spec.
Ask three things: does the supplier hold retains, for how long, and will they release one to a third-party lab on request. A supplier who holds retains and will let them be tested independently is telling you something about their confidence. So is one who will not.
Hold your own too. A retain you control is the only sample that cannot be swapped.
What "in spec" should mean
It should mean one thing: every listed compound fell inside its stated tolerance, measured by the named method, on the lot you received.
It should not mean the certificate looked broadly similar to the last one. It should not mean the supplier's internal panel was happy. And it should not depend on who is asking.
If your supplier's certificate reports fewer compounds than your specification lists, your specification is not being tested. That sounds obvious written down, and it happens constantly. A standard panel reports the dominant terpenes, and the compounds that make a cultivar recognizable are often present at fractions of a percent, below the reporting threshold. Our guide on reading a terpene COA covers what those documents do and do not tell you.
Writing it so it survives a supplier change
The best test of a specification is whether you could hand it to a different supplier and get the same material.
That means writing it against the material, not against the supplier. A spec that says "Blend 4471 from your Native® line" is a reorder instruction. A spec that states the compounds, targets, tolerances and method describes something any competent formulator could work to.
This matters more than it sounds. It is the difference between a supply relationship you chose to stay in and one you cannot leave. We wrote about the mechanics of moving in switching terpene suppliers without reformulating, and the single thing that makes it survivable is having a real specification before you need one.
FAQ
What should a terpene specification include?
The compound list with target concentrations, a tolerance on each, the analytical method used to verify them, appearance and any physical limits such as viscosity, and the process that runs when a lot fails.
How tight should terpene tolerances be?
Tight enough to protect the compounds that carry the character, loose enough that honest botanical variation passes. Set them empirically by measuring three lots rather than by choosing a number that sounds rigorous. A tolerance no honest lot can meet produces a monthly argument, not quality.
What is a retain sample?
A sealed sample of the exact lot shipped, held by the supplier and ideally by you as well. It is the only way a batch dispute becomes a lab question rather than an argument about material that no longer exists.
Why does the analytical method need to be in the spec?
Because two labs running different methods on the same material can return different numbers. Without a named method, "in spec" means something different to each party.
Can I use the same spec with a different supplier?
That is the test of whether it is a real specification. If it describes the material, yes. If it names a supplier's product code, it is a reorder instruction and it does not transfer.
Where to take this next
If you are buying against a strain name and a volume, the next lot that disappoints you will be unresolvable. Write the spec first. Send us what you are working to and we will tell you which parts of it we can hold to and which parts need a number they do not currently have.
About the author: The Entour™ team is a division of The Werc Shop®, the first commercial cannabis laboratory to test for terpenes back in 2011. The team formulates True To Plant® terpene profiles for licensed cannabis brands across the US, Canada, and tribal markets.
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