Sun Rendering Fish Oil

by Jonathan J. Weber
Northwestern New York State

In making fish oil, consideration should be given to the purpose of the rendered product. If the oil is intended for use solely as liquid bait, many species of fish are suitable. However, the oil when intended for use as a lure base should be light-textured, neither lumpy or rank, therefore trout, perch and similar species of fish are recommended.

The only equipment you will need is a large glass jar, gallon size or similar, and a pane of glass. After cleaning the fish – remove the entrails – cut in into cubes the size of one inch squares. Do not fill the jar with cubes but rather place them into it so about two thirds (2/3rds) of the jar is full. The jar should then be placed on a side-hill or in a cleared low-cropped field and where the morning and afternoon sun will warm the contents. Other good locations are on the roofs of sheds or other outbuildings. The glass pane is placed on top of the jar, weighted down with a stone so that it will remain stationary and prevent air from penetrating freely. It should not be so completely pressurized inside the jar that gases cannot escape, yet it is important to realize that the pane of glass must be held down tight enough to prevent blow-flies and maggots from turning the material into rot and stink. If you see that you are going to have trouble with blow-flies, then do not use the pane of glass. Instead, place the jar lid into position but do not tighten it so securely that gases cannot escape. Wrap several rags around the jar lid and over it and secure it in place; this will stop blow-flies from penetrating. The mid-day and afternoon sun will cause the cubes of flesh to begin “working” (bubbling), which is the start of the rendering process, and after several days the oils will begin to rise, almost unnoticeable at first, and settle on top. At all times, keep an eye peeled to assure that blow-flies are not making their way inside. If you have to, place a screened box over the jar.

The time element involved in sun-rendering cannot be pin-pointed as local weather conditions will be the determining factor. In this respect, the best advise is to suggest that the process be examined periodically and thus gauge how it is working. In some areas it may take two months, in other areas much longer. When you feel the oils are free of flesh, your own judgment should end the process.

The oil that rises to the top should be spooned into a separate container. After a few days, remove oil that has re-formed in a lighter coating and add it to the contents that were already removed, continuing to do this until you feel all the oil has risen.

It is the oil that rises, called “TOP OIL,” that is most valuable. If desirable, the semi-broken and partially decomposed cubes can be strained to free them of the other oil that has settled on the bottom of the jar, then placed in a separate container for use as bait. The lesser quality oil, in the form of juices more then oil, should not be discarded as it can be used as the base in some lures or mixed with glycerin oil and various musks and other ingredients in producing fine quality raccoon liquid bait or bait solution. Store each container in a cool dark place or bury them just below the ground level in a shaded area until ready for use, but not beyond the winter freeze. Don’t tighten the lids on the jars when in storage until you are positive that developing gases have quieted down to such extent that all gases have dissipated.
I mention this because some species of fish are more gaseous then others. Your storage site should be in a place that is free of insects and contamination of any kind. *

This method of sun-rendering fish oil will not turn you into a large commercial fish oil manufacturer, but will provide sufficient quantities for personal use, and you will have as good sun-rendered fish oil as money can or cannot buy!

Best time to sun-render fish oil is during the months of May through August, and there are times when the entire period is required to produce a good product.