I know the basics of finding the biomass of something - stick it in the oven and cook it until all the water has vaporized. Water is not biomass; water is not *living *(bio in biomass).

But what temperature should I set the oven to? And how long should I cook the object as to ensure all the water has been vaporized? Anyone with any personal experience?

I think that you’re thinking of ash. The name might give some indication of what you’re targeting at the end of the day.

Ash would imply combustion, which would remove most of the weight of a living object. C turns into CO2, and plenty of other combustible and/or volatile substances also are removed in combustion.

I’m pretty sure biomass is just the dry weight as the OP asks for. Looking at definitions online, I find many that specify dry weight.

I don’t know if an oven is necessarily the best technique, but I’d recommend a temperature of 150-200 F. (This is about what’s used for making beef jerky). The length of time depends on how thin your specimen is. For 1/4" beef jerky on a rack, 8 hours is sufficient, but I suspect a whole roast would take several days.

Of course, you could use a dehydrator that relies more on moving air than on heat. My dehydrator (which we use for fruits) puts out only a little extra heat; I doubt anything in there gets over 90 F. Again, time depends a lot on thickness. 8-12 hours is good for most slices.

Neither of these methods can get you to exactly 0% moisture content, but they’ll get close.

Somebody fight (or confirm?) my ignorance here. I believe biomass is defined and calibrated as the weight of the carbon in the sample. A real sample, even fully dehydrated, still contains some amount of other elements, but only the weight of the carbon counts. So this has to be computed by some biometric process that teases out the weight of the C from the weight of everything else.

From Wikipedia article on biomass:

From the introductory section:

(Bold added.)

The measurement might be a total amount (grams or tons), or a productivity measurement (grams or tons per year, e.g.), or a density measurement (grams per square meter on land, or grams per cubic meter in the ocean).

Thus you might see measurements with units like these (from farther down in the same wiki):

ETA: I learned about this stuff while writing a term paper on bioproductivity in the ocean, in an introductory oceanography class I took some 25 years ago.

It matters what you’re trying to measure. A spider? A pile of algae? Your annoying younger sibling?

I usually have a student per term attempt to do similar measurements for their project, so I would be happy to help you with tips if you let me know what substances you’re working with.

The test you want to run is called a proximate analysis.

A weighed sample is heated at a certain temperature and time to drive off moisture. Then you do a test for volatile compouds such as** fat**. Then it is burned to determine the ash content. This may involve a moisture meter and an oven and some other equipment. Do you have access to lab equipment?

You will end up with a certain percent that was moisture, then volatile/fat, then ash. Subtract these percentages from 100. The missing amount/percent is the **nitrogen/protein **or what you are referring to as the biomass.

I am familiar with the analysis as it applies to feedstuffs but the test methods are the same.

Research proximate analysis. This might be what you are looking for.

Thank you, and thank you all for the advice, suggestions, and help. Ice Cream, I will PM you.