A very concentrated broth

This week I managed to get my hands on some large beef bones (weight-bearing, probably femur). They are very large and as I don’t have a saw handy in my ordinary domestic kitchen, they have to be used as they are.

Bone number one went into the slow cooker with a little thyme and cooked for around seven hours, creating a lovely aromatic and slightly fatty broth. Then, following the procedure I have been using recently with chicken and chicken bones, I decided to put bone number two in the same pan, with the same broth. This produced something quite different from what I expected – a concentrated, extremely fatty consistency. At a rough visual guess, I would say almost half fat and half water.

Beef femurs like this carry connective tissue, cartilage and surrounding adipose tissue. Prolonged moist heat converts collagen into soluble gelatin and renders the fat. Obviously, reusing the original liquid increased both the amount of extracted material and its concentration relative to the water.

The ‘experiment’

 

The first bone produced a nice fatty broth. The second bone was cooked in that same broth

   

Once cooked for several hours, the ‘broth’ was very, very fatty indeed. I had created a concentrated mixture that was suitable for dilution in other dishes.

   

The two sessions also produced a translucent, gelatinous mixture of residual meat, fat, possibly some cartilage and likely softened collagen-rich connective tissue.

 

Blitzing strengthened the emulsion, producing the pale, creamy mixture shown here. To avoid gastrointestinal mishaps, I decided the best path would be to portion and freeze this. The individual blocks can easily be added to a puree or a bean and vegetable stew, for example.

 

To even things out (and to avoid sieving every last bit of meat and fat out of the liquid), the rest was poured out of the slow cooker and into the blender and blitzed as well. It’s clear from the result that there was still quite some ‘structure’ in what was left in the pot.

Practicalities

Clearly, this is too fatty and rich to deploy as a hydrating drink and probably unwise to use without dilution in a sloppy Joe. However, on reflection, I realised that this unexpected outcome had been useful and was worth repeating: a concentrated broth would take up less space in the freezer – and even perhaps save on time and effort overall.

Glass-half-full thinking!

Ready for the freezer

Frozen portions of meat, fat and softened tissue

Nutrition

What is in this apparently simple liquid? In a bovine broth study this year[1], scientists identified 17 amino acids in the broths. Glycine, alanine, proline, aspartic acid and glutamic acid were among the principal ones. Collectively, these amino acids are involved in connective tissue formation, antioxidant synthesis and energy metabolism.

Perhaps more importantly, the broth itself is a food structure. It isn’t simply water into which individual nutrients have leached. It is a food matrix: an oil-in-water system containing fat droplets, proteins, peptides, free amino acids and other dissolved or dispersed compounds.

Cooking tip:

A rolling simmer develops and intensifies flavour more effectively than cooking at a lower temperature[2].

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Licking the bone clean!

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References

[1] Zhang Q, Zheng M, Lu Z, Zhao K, Wang S, Li B, Hu Z, Zhang S, He D, Lei F, Zhou L. Operational parameters and key characteristics of amino acids and flavor compounds profiles of bovine bone clear and white broths. Food Chem X. 2026 Jan 16;33:103553. doi: 10.1016/j.fochx.2026.103553. PMID: 41623986; PMCID: PMC12853060. https://pubmed.ncbi.nlm.nih.gov/41623986/

[2] Moon S H, Kim J, Hwang K T, Cha Y B. Physicochemical and sensory characteristics of beef-bone broths prepared under atmospheric pressure and overpressure. Korean Journal of Food Science and Technology, 47 (6) (2015), pp. 725-732, 10.9721/KJFST.2015.47.6.725

 

Important Considerations:

  • Always consult your veterinarian before making any significant dietary changes, particularly where there are pre-existing health conditions or dietary restrictions.
  • If you are feeding commercial food, check the label for ingredients before giving more. Excessive intake of any foods can have adverse effects.
  • Ensure (where possible) that you use high-quality, organic products specifically formulated for pets (or better still, human grade ingredients) to avoid any potential adverse effects.
  • Introduce new foods gradually to avoid adverse effects such as gastrointestinal upset or diarrhoea.
  • I provide nutritional information purely as a helpful guide. Nutritional information on ingredients is obtained from the US Department of Agriculture’s FoodData Central site (https://fdc.nal.usda.gov/index.html) and any nutritional information provided in recipes is based on an online calculator: calories and other information will vary based on brands, ingredients and other factors.
  • Check nutrient levels and recommendations for your dog’s weight, age and activity. For example this nutritional guideline produced by FEDIAF.
  • I am not a professional canine nutritionist but supporting research is cited.
  • The recipes shared were created by me and tested in my kitchen – and tasted and approved by our doggy friends!