How Long Should Hides be Aged? – Scent Work Competition FAQ

How long should you age hides in scent detection?

Pat’s question: How long do you age a hide prior to the start of a nosework trial? Is it the same for all the elements?

Answer: Aging is the amount of time between placing a hide (containing target odor) and the dog’s search. I’ve seen from 5 minutes up to hours of aging tested in UKC nosework competition. That’s true for containers, interiors, exteriors, and vehicle searches. (Pre-trials should be testing odor recognition only, so hopefully they’ll present minimal aging of less than an hour.)

Working scent detection K9’s need to be able to find aged hides. For example, bedbugs may have infested a mattress for months before the canine inspection. Cadaver dogs may find human remains in a tree or under water after months of aging. Scent dogs needs to learn to detect target odors in small and large amounts, and all varieties of aging, for reliable performance.

While aging, scent disperses in its environment until it reaches equilibrium. Don’t forget scent is shaped by complex interactions of variables including room size, ventilation, airflow, surface area and temperature. “For any given hide, the larger the area in which the hide is placed, the longer the time it takes for that environment to reach equilibrium”(1). Further, inaccessible hides affect odor availability to the detection dog. For example, let’s say you set 2 hides:

  1. An inaccessible, “deep” hide might be a hide inside a semi-sealed container placed inside a garbage can with its lid closed.
  2. An accessible or “shallow” hide might be the same container lying open in the sink.

The inaccessible hide needs significantly more aging time in order for it to be available and detectable to searching dogs. In comparison, little aging is required for the more accessible hide to disperse freely in the air and be detectable to scent dogs. (So in the case of inaccessible hides with little ventilation, more aging is easier for dogs to detect than no aging at all.)

For newbie teams learning scent work, try to make the hides easy by presenting well ventilated, avoid inaccessible hides, reduce wind and distractions, and age approximately 1-30 minutes. As confidence increases, gradually introduce aging up to several hours or days (scroll down for details).


Question: Dang – that’s a long time, then. Why on earth would they age something for hours before the trial starts?

Answer: Here’s one example:

  • It’s a sold-out trial. The next event has 20 teams searching
  • Time = 0 Set the hides while previous event is running
  • 15 mins – intentional aging
  • 20 mins – dog in white
  • 25 mins – brief the event. Max search time is 5 mins
  • 35 mins – first dog starts search
  • 5 minutes between every search = 5 x 19 = 95 mins
  • 130 mins – last team starts search

If teams aren’t waiting on the line, or club takes a lunch break before the event starts, or weather is challenging and your start line is repeatedly blown or rained away, or have trouble setting up vehicles in vehicle search, or any dog has an aggressive alert and search needs to be reset, or cleanup of feces, or you have to rerun some teams, or there’s an injury, or judge is called away to answer a question, you could end up with longer aging.

Since dogs can find target odor after hours or days of aging, why not be prepared? You have a choice between training or complaining.

Prepare for any aging (between zero and hours or days) and you’ll be ready when your skills are tested.


Question: How Should I Train for Scent Work with Aging Hides?

Answer: Start by aging a few minutes longer than usual and then gradually increase the time. Observe whether your dog is just as confident.  Over time, you want to expose your dog to short aging, long aging, and everything in between, so he doesn’t know what to expect. That way, no matter the aging you are presented with in a scent work competition, you will be prepared.

Introducing aging can be as simple as searching a hide after 10 minutes aging, leaving it there and coming back 10 minutes later to repeat the search.

For example, during imprinting in our Level 1 classes, dogs repeatedly find odor in a hot box that is moved around the scent detection lab. When I place a hide at 6:15 pm and run the dog in white, beginners will start searching for it at 6:30. Level 2 students start searching for it at 7:30. Level 3 students start searching for it at 8:30pm. It’s fascinating to watch the search patterns change as the scent disperses over time.

For more advanced scent detection teams in Sniff Alberta, we’ll place a hide at the warehouse on Wednesday, and teams will search for it on Saturday.

Try getting your training partner to place a hide and run their dog as dog in white to verify, then leave it there for a week. Post a photo of the location with the GPS coordinates or Google Map online. Then you’ll know exactly where to search for the well aged hide over the course of a week.

How do you practice aging for scent work? Join the discussion by posting a comment below.


  1. Canine Olfaction Science and Law (Advances in Forensic Science, Medicine, Conservation, and Environmental Remediation), Ed. Tadeusz, J. et al, page 272.
About carlalsimon (90 Articles)
Dr. Carla Simon is a Scent Detection Instructor, Certifying Official (UKC Nosework), and President of Sniff Alberta. She’s been breeding and training scent dogs for Hunter’s Heart since 1999. Carla's evidence-based, motivational training has helped hundreds of scent dogs to reach their potential, with target odors ranging from human scent to bed bugs. Follow her Nosework & K9 Scent Detection Blog at:

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