Showing posts with label yield. Show all posts
Showing posts with label yield. Show all posts

Saturday, March 8, 2014

Tallow 3

In which I overcook the tallow

Another trip back to the market, and the butcher generously provided me with 2.1kg of assorted fat. I added the 600g of tallow from Tallow 2 as a heating medium rather than water, and simmered. This produced approximately 1.5kg of tallow total.

Darker tallow


Unlike Tallow 1, I let the rendering continue at a higher temperature well into the browning stage, so the resultant tallow was significantly darker than my previous efforts.

This could be for several reasons:
  • Some fraction of the fat might have reached its smoke point and decomposed, leaving carbon with sufficiently fine grain to pass through the filters.
  • Some substance from the meat or connective tissue might have dissolved into the fat, giving it a darker hue.
  • It's possible there's some mineral in the tap water that's promoting darker tallow.
Or any number of other things.

Clarifying the tallow


I remelted the tallow at very very low heat, then let it set. The underside of the tallow contained the majority of the darker mass. I scraped it off, then repeated the process. On this second run there was also a dark mass on the underside. I scraped it off and repeated a third time. On the third run, there was no dark mass to scrape off, nor on the fourth. Apparently the tallow had reached its maximum clarity even though it wasn't white. I had removed a total of 429g of tallow and "dark stuff".

Lower yield


The total yield from the preceding experiment and this one was almost exactly 1kg of tallow. That was less than I had expected.

The tallow, being very very soft, was harder to manipulate and transfer from pot to pot, leaving a fraction of itself behind at each stage. I would hazard a wild guess that 10-15% of the total was lost on the sides of pots and pans or poured out with water.

Future attempts


If I have a large enough batch of fat in the future, I shall try as follows: split it up into four batches, and try low-vs-high temperature, and distilled-vs-tap water.

Tuesday, April 23, 2013

Saltpeter math

Nitrogen: The math

From Wikipedia
  • Grams of urea in a liter of urine: 9.3
  • Molar mass of urea: 60g
  • Molar mass of potassium nitrate: 101g
Break out the Unit Factor Analysis manual...

So to get 1kg of Potassium Nitrate, you would need about 32L of feedstock.

Saturday, December 29, 2012

Potash 2

Another run, this time being more careful to filter insolubles, not crystals being formed. Yield 7.6%.

Saturday, December 22, 2012

Quicklime 2

This time around it was 50g of chalk in and a couple hours on "high" in the kiln. 28g of lime came out. Since the ratio of molecular weights of calcium carbonate to calcium oxide is 100:56, that is dead on correct. Huzzah.

Day 14: in a clay pot with a loose lid, it appears to have reverted completely.