For this section of experiments I continued to use the lump charcoal open fire for heating ( This time at a different friends house) and because I had to gather new water we switched to a super saturated brine. This means I boiled the ocean water just until salt crystals started to form in the pot.
To continue the hypothesis that soaking the cup in water would reduce the amount of salt seepage I soaked a cup in bottled water for a full day prior to this attempt. I chose bottled water so that there would not be added chlorine, fluoride, or other chemicals bringing it as close as I could get to spring water. While this seemed like an unlikely method, given that they were right next to the ocean and therefore more likely to soak it in the ocean water if they did at all, it felt like an important control method.
I also soaked another cup in unevaporated ocean water for an equal amount of time and once I obtained the use of additional cooking space, I added a dry cup for comparison. In the remaining attempts I wanted to test my layered boil hypothesis in order to get a solid pack rather than the lighter flaky results that were easily dislodged in my first experiments.
Experiment 8: Direct Boil over an open fire – Fresh Water Soaked Terra Cotta, Layered fill
Experiment 8: Direct Boil over an open fire – Fresh Water Soaked Terra Cotta, Layered fill
For this attempt I wanted to repeat the process started in attempt 7 using a water soaked with repeated fills to see if we could reduce the amount of salt seeping through the cup. This hypothesis proved correct however there were some negative effects too.
It took longer to boil down the brine in this cup than in the salt water-soaked cup or the dry cup. In addition, a small crack developed over the course of the day. This may be a flaw in the pottery and no leaking occurred. I did not get to a solid fill in the cup by the end of the first 8 hours but, I did not want to waste the day’s experiment even though there was still some liquid in the bottom even when the other two had dried.
Due to the crack, at the end of the night I risked burying it in the coals to complete the evaporation of the liquid remaining. Because the clay was already warmed from the time over the fire, I was able to quickly boil off the last of the water and allow it to slowly cool with the coals.
Experiment 9: Layered Direct Boil over an open fire – Salt Water Soaked Terra Cotta
Since good sources of fresh water are less common near the ocean (and would dilute the salinity levels needed for making salt), it seemed unlikely that would have been a common process. Since I still wanted to test the hypothesis I decided to attempt soaking in salt water as well. This produced a thin salt crust on the outside like attempts 7 and 8 but still less than the early attempts.
Despite doing my best to ensure attempt 8 and 9 were heated evenly the brine in the salt water-soaked vessel evaporated much faster than that in the fresh water vessel. Despite this and being able to refill multiple times through the day the process overall was still slow enough that I was not able to complete a full cup of salt in the 9 hours we attempted the first day.
Similar to the fresh water soak a tiny crack formed near the bottom of the cup. On close examination it seemed to be mainly in the surface salt and a decision was made to continue to experiment using the same cup with revisions to our process for day 2. The results of the continued experiment are under attempt 11.
Experiment 10
I had been leery about running a control cup that was not soaked due to the limited space on my tiny grill. Once a second grill was obtained however, it made sense to use the heat we were generating to try a dry cup. This was several hours after the initial batch had been started so it could not be a true control, so I made some process modifications.
Given the very slow evaporation that was occurring in the water-soaked cups (and the delayed start) the decision was made to start with only 150 ml of brine at approximately 2:20 pm. Water was then added 100 ml at a time. This cup also tragically developed a crack during the heating process over the course of the day and so it was decided not to repeat the use for day 2.
It was at a higher elevation over a hotter heat source than the soaked cups, so it is more accurate to compare it to experiment 5. It produced less salt on the outside of the jar and a similar amount on the inside . I concluded the greater distance over the along with the more consistent high heat from the ability load fuel more easily without disturbing the vessels may have had a factor in this leading me to believe this new stove may be a better choice moving forward.