In discussions regarding aging/tainting ingredients for lures and baits, there are frequent comments about venting the container that the product is in as it ages. I am curious to know if proper venting is needed for the ingredients to age properly or is it more about not blowing up the container? Does it age differently if it doesn’t have enough oxygen? I am also wondering if the same goes for rendering oils, such as BTO or skunk oil? Thank you for any input you can provide.

You do not need to vent a container when making BTO. Aging glands I don't vent the container, but I do crack the lid every few months and it will have pressure built up. For me I vent to avoid blowing the container. I don't know, but I assume that stuff does age differently when in a controlled environment without venting and who knows what flowing in on the outside air.

I have limited experience with a lot of this though and will be interested to read the experts opinions.

I am no expert but have many years of experience and dealing with such things which I will share.

Oxygen facilitates the breakdown and aging process. Most all materials will have some breakdown gas released as a byproduct while being aged.

Proteins, like meats and glands are the ones that cause the most attraction to blow flies. They create the most gas release however, venting is needed to some degree or a regular container bleeding habit so the container does not break or rupture.

High fat content materials like beaver tails and other scrapings with high fat content ie. ( skunk fat ) in general have moderate gas off. Remove the skin from the tails and there will be very little gasing. Flies that do get into these types of rendering containers don't last long once the oil develops. They drown. These can be removed by straining at a later date along with any egg clusters that may have been laid.

Due to the volume that we do, venting with an installed venting port near the top rim of a bucket is mandatory. This way there is very little maintenance needed for gas release nor worries about flies. Just inspect occasionally for product condition and stirring if needed.

If you are no expert Bob there isn't much hope for a guy like me, lol.

Smaller batches of materials that I age or sun render, i leave the cap a little loose and seal it off with blue masking tape to keep flies out and still allow gas out. The tape leaks just enough and still provides a maggot barrier. I have done this on gallon jars on down with no trouble, left in sun all summer too.

My rule:

Fat = no gas.

Meat/membrane = gas.

Glands = gas.


I vent my BTO because I use the entire tail so I do see light gas production.

I do not vent straight skunk fat trimmed off the carcass, but I DO vent skunk scrapings as there is enough membrane and meat in there to produce a slight amount of gas.

I vent all glands. A short length of tubing and an airstone is cheap insurance versus cleaning up a mess and possibly loosing an entire batch to flies or such.

I have found different reactions do to elevation. I vent everything. The old saying, better safe than sorry. Just my own insurance policy.

Elevation affects cooking, baking and rising goods as well.

Amen to that Bob! My gal has had good and bad results with mostly bread but shes got the kinks worked out of it now. Wish I could say the same with my formulating and science projects of dead animal parts!

Elevation also affects carbonation levels in beer.

Thank you for all the replies. I was expecting there to be some comments about aerobic vs anaerobic processes, but sounds like the biggest concerns are related to pressure or insects. I have a bucket of fresh ground beaver that I am looking to get to that just right sweet taint. Thanks for the information.