Saltpeter boiling de ja vu

April 28, 2010 at 8:34 pm | Posted in saltpeter | Leave a comment

Today I started boiling down the saltpetery liquid. I had to wait until I was alone in the house because past experiences suggested that it would not smell very pleasant.

Speaking of the smell it’s interesting. The first time I tried this, the liquid smelled awful, and then when I started boiling it, the smell changed to be much more palatable. Still unpleasant, of course, but no longer disgusting. This time around, the liquid had almost no smell (which I attribute to the soil being further along in the composting process), but when I started boiling it, it almost immediately changed to have the exact same scent as the first batch.

Biringuccio says that the “Each time it boils, it forms a foam and swells up so much that if one is not watchful…much that is good is carried away”. The first time I made saltpeter, there was no almost no foam at all, except when I added alum in a later stage. So today, I put the pot on to boil and then left the house to walk to dog. When I got back from the walk, I was shocked to see that my pot had foamed up substantially and was on the brink of boiling over. I turned the heat off, and the foam sunk down. When I turned the heat back on, the foam popped up immediately. I was thrilled, since this meant I was closer to being on target with what Biringuccio says should happen.

Here is a not-very-good picture of the foam. It’s hard to see, but unlike the airy, insubstantial alum-induced foam from my  first batch, this foam was much fluffier, and solid-looking. It reminded me of meringue, and I was almost surprised that it didn’t have a firm meringue consistency.

Since I was getting spectacular foam, I decided to immediately try Biringuccio’s remedy of lye and alum. Last time, I made my own lye, but repeated attempts just aren’t producing a strong enough lye on my own, so I bought some online. Apparently lye is illegal in Massachusetts, but luckily for me, the internet shippers didn’t know that. I was surprised when it came in pellet form, but I was able to dissolve the pellets in water to more uniformly pour into my saltpeter liquid.

The alum had the same effect that it did last time: its introduction made the foam even more explosive. The lye’s effect was exactly as predicted: it made the foam go away. Even more interesting, it kept the foam from rising again! Once the lye had been added, the foam never came back.

I am still in the process of boiling the liquid down to one third of the original capacity. When I’m done with that (and have burnt some nice smelling candles in the house!), I will be putting it aside to settle for a week or two, after which there will be more boiling, more lye, and then hopefully congealing saltpeter.