Thermal limits can be increased in bone. We are attempting it in our kitchens. A massive info dump and photos inside. Included: photos of what happens when grease bakes into bone.
We know that it is possible to raise the thermal limit of bone. This is achieved the same way it has already been done in hides, bone and other type-1 collagen structures which is by adding cross links to collagen or modifying the collagen in other ways. Generally speaking, aldehydes are probably best at it with certain ones raising the limits up to 82 C. These come with consequences. The changes are permanent, and they might add tension to the collagen. As with heat-shrinkage induced tugging, any other kind of tugging may also stress the hydroxyapatite lattice and slowly pull it apart. So, the goal is materials that improve cross linking like aldehydes, but temporarily, or can help in other ways, like certain glycols, by "coating" the collagen molecule and acting as a sort of heat sink while present.
We have gathered information, consulted collagen experts, visited labs, passively tested and innovated. This week we have made serious attempts at increasing the thermal limit of bone in our kitchens using safe, simple and easy to obtain materials. It is not recommended people mess with tried and true heat limits on bones they care about. This is just a ton of free information, and early results. We strongly recommend not exceed 44 C for adult mammals.
The skulls and jaws you see were beetled. The jaws were not degreased. To start we decalcified many jaws to observe the changes in shape and size as collagen was impacted by heat. We deliberately overheated bone to the breaking point to see how far we can push these materials. There were two cooling stages to help collagen recover.
The jaws have their times in hours written next to them and were done at 56 C with only exposure to the cross linker. If there is no number next to them, they didn't get exposed to heat and were just left to dry. The skulls were done at maximum boil settings, over 100 C because of the chemicals added, and had the full roster of chemicals thrown at them with no decalcification. This is done because collagen in bone is notably tougher than outside of bone. They were watched for turbinate mobility/damage, nasal mobility, tooth loss and zygomatic warpage. Turbinates typically are the first to fry, and let us know that a time/heat overstep has occurred. In canids, the nasal/maxillary joint dislodges and rises, and the zygomatics warp and displace early in in bone warpage.
Observations so far include a doubling of critical failure time of decalcified marten jaw from 4 to 8 hours and warpage and shrinkage starting to ramp up at around 2 hours in the jaws. This is scheduled to be repeated next round. Warpage and shrinkage is bound to happen as they dry, so observations were made both wet and dry. These were photographed dry. The coyote bullet wound was treated. It was examined by a forensics masters student who decided that the cracking had not expanded despite a heating and cooling phase and exposure to temperatures over 110 C. The expectation is that cracks should expand rapidly in these conditions. The ethmoid and turbinates in this specimen are flaking though, indicating an overstep in heat exposure. Another cool observation is that in the treated water there was not foaming, but in untreated controls the foam got out of control.
The heat bracket appears to be around 54 C to 80 C for possibly two hours, with time scaling with lower temperatures and more robust bone. It is likely that 60 C to 70 C for 2 hours is the sweet spot with full treatment, because literature indicates 60 C to 62 C is the uppermost bracket for robust bone before shrinkage and this is also apparently meat glue treated collagen thermal limit. Untreated, 60 C gives about 30 minutes of exposure time before damage in non-bone bound collagen, shrinking to just minutes or less at 70 C. Expanding this ability should land us somewhere in the 60s C for an extended period of time or higher for shorter times which allows rendering of many hard fats.
Application: Brute force removal of grease on the front end of degreasing, moving hard fats easier. This may make some of the more notorious dense boned greasy boys like bears speed up.
We may not finish this work all at once because we need to take time to think about and consider our results. We also want skulls to sit for a while. This consumes a LOT of test specimens. Specimens are currently demineralizing for another round with more refined temperature exposure and more specimens are being sourced.
Materials used: Glycerol (Glycerine), our powder degreaser, peroxide and a sub-optimal temporary collagen cross linker chosen for safety and availability. Some jaws decalcified with EDTA, some with vinegar. Those handled in the photos were decalcified in vinegar.
https://www.instagram.com/bare_bones_solutions/ for updates
Methods may be made more available if we can get them to work.
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Here, we present photos of gelatin, bone and oxidized fats and a smoking gun of them interacting (red circle).
When bone is heated to excess people claim that fats "move deeper into the bone" or "bake into the bone". We have hypothesized a few different causes, and have just seen first hand that one of them is correct. Fats remain relatively in-situ as collagen turns to gelatin and are absorbed via emulsification.
Simmering temperatures (80 C- 90 C) are ideal for gelatin production from collagen. Gelatin is sticky on smooth surfaces. Inside a wicking, non-smooth surface like bone it becomes more difficult to move. When fats are overheated, they oxidize more readily, turning black and becoming more resistant to some non-solvent cleaners. If you are thinking about the clear looking grease that is difficult to move, it is actually pretty easy to move. We smoke it all the time with our spot degreaser, it just needs an appropriate solvent.
These gelatin-oxidized fat wicked-into-bone nightmare blobs are not moving deeper into the bone, they are already in the bone waiting to be transformed by excess heat. As they cool, slower with insulation from the bone (which is a decent insulator), there is a chance the fats may crystalize, making them even more resistant to soaps. This part seems pretty uncommon though.
Small amounts of glycerol in water, which is one way to dissolve gelatins, at high temperature have yielded no such oxidized fats or gelatin with overheated skulls.
Thank you for coming to the ted talk. This is some of the cool stuff happening at Bare Bones.