The Fugue

If my last post made your head spin, you're not alone. It made mine spin too when I was conceiving and writing it.

For your sanity and mine, I have put together a soap calculator spreadsheet. You tell it the precision of your scale, how much of each fat you want (sorry, you have to specify the saponification value too, but there's a reference chart included), and your target lye discount. It tells you how much lye and water or milk to use. It also tells you how the measurement error effects your expected lye discount, and warns you if your soap might turn out lye-heavy. You can easily scale the recipe arbitrarily.

Download the calculator and my recipes at http://hans.fugal.net/soap.

The OS X Leopard Calculator has one very nice change. A picture is worth a thousand words and I'll let this one speak for itself:

Speaking of calculators, I once came across this gem and then inexplicably forgot all about it. It's called orpie and it aptly dubs itself the mutt of calculators. It's RPN, it's curses, it's at least as rich and powerful as your HP 48G (in features, that is), and it's completely configurable a la mutt.

A few standard tricks to get it compiled on OS X:

sudo port install ocaml gsm
export LDFLAGS=-L/opt/local/lib/
export CPPFLAGS=-I/opt/local/include/
./configure
make
sudo make install

I set up iTerm to run orpie in a new tab on ctrl-cmd-o, to ensure that I never forget about this powerful calculator again. Go ahead and give it a try. It's like an HP 48G, but unlike x48 and other emulators, it's actually usable from the computer keyboard.

So as not to leave anyone hanging from my last post, here's what I do from beginning to end with regards to calculations when baking sourdough bread.

First, I decide on quantity. I bake a loaf of whole wheat sandwich bread every week or so (sometimes sourdough, sometimes no), and 800g is a good dough weight for that. For a sourdough boule, I aim between 300g and 500g. For experiments and baguettes, 250g or less. For big boules or loaves to fit the more normal size loaf pan, to take to functions for example, I aim at 1kg. The beauty of it all is that I can make whatever amount of bread fits my needs, with a few minor calculations.

Now that we have the dough weight, we need to break it down into the various ingredients. Most ingredients in baking are relative to the flour used, so flour is the first calculation. I divide the total weight by one plus the hydration baker's percentage, i.e. if I want a 66% hydration dough I do flour = dough / 1.66.

Next we need the amount of water. water = flour * hydration. For our 66% hydration bread that's water = flour * 0.66. 66% hydration is a really nice number because not only does it make good bread, it has a good margin of tolerance for measuring mistakes (you can go a little drier or wetter with no worry), and it is easy to do in your head. That's right, 66% is two thirds. 300g flour and 200g water makes 500g dough and it's easy to remember/calculate even without a calculator.

All that's left is the salt and leavening. Salt is about 2% of the flour. I read 1.8% somewhere and it stuck so that's what I use, though I know my measuring is nowhere near that accurate for the amount of dough I make. So 300g * 0.018 = 5.4g. Alas my scale measures 5g increments which is mostly useless for measuring salt, so I asked units what to do:

You have: 1 g
You want: tsp salt
        * 0.16666667
        / 6

Oh, well that's easy to remember, just divide the salt weight by 6. So salt = flour * 0.018/6 teaspoons.

With yeast you just guess. Take a similarly sized recipe and use that much. Bread recipes all vary so much here anyway, and the different kinds of yeast do too. Just remember, more yeast means faster rise and less desirable flavor. Less yeast means slower rise and better flavor.

If you're doing sourdough, I hope you haven't mixed the flour and water yet because there's going to be some adjustment. Decide how much start you want in proportion to your dough. 10% or 20% is easy to do in your head. Now do the same thing with flour and water as above, for your total start amount. Or, be lazy and use 100% hydration start and divide by two (by weight). e.g. for our 500g loaf with 20% inoculation we want 100g start, so that's 50g flour and 50g water (plus a little start from the fridge, about 10g will stick to the side of your container anyway). Subtract the resulting flour and water amounts from the calculated flour and water above (or do the start calculations first).

If you want to add honey, sugar, oil, butter, seeds, whatever else, just follow what a similar-sized recipe calls for or eyeball it. Really the only things to fret here are the flour/water ratio and the flour/salt ratio.

All that probably seems a little overwhelming, which is why my sourdough script and sourdough calculator webpage exist. But if you're lazy/cheap and can memorize a few unchanging equations (but can't memorize a recipe for 5 minutes to save your life), that's how you do it.

I have the {sourdough,} bread formulas that I use memorized now, so I rarely use my little script anymore, instead opting for a calculator and my logbook. As a result I've been taking my precious HP 48GX (or sometimes even my laptop) into the kitchen, which always makes me uneasy, especially since the 48GX is nigh unto irreplaceable. So I bought a calculator yesterday.

I had no delusions that there would be a $5-$15 RPN calculator, so I picked up the most fitting $10 calculator from Target, which happens to be a TI-30XA. It's a little scientific calculator with way more features than I expected to find for $10. HP makes a model in this range too, the 9s I think. I honestly don't know if it was even on the rack at target. The TI-30XA was closer to my eye level and maybe a dollar or two cheaper, if there were any comparable HPs.

My point is this: cheap calculators is a cutthroat commodity business. There may not be a big market for RPN, not enough to justify an RPN model perhaps, but if someone out there made a $10 calculator that was RPN, even if it was only 4-function or reduced functionality scientific, that would differentiate that calculator in a measurable way. No, it's not going to corner the calculator market, but it couldn't hurt, could it? I'm a programmer, and I've written toy calculator programs in various languages including assembly. It's a lot easier to add RPN functionality than this algebraic entry stuff or plethora of fancy trigonometry and biology (I kid you not) features. I have a dream that someday some company will get their act together and offer a calculator similar to the TI-30XA that is RPN (or can do RPN). If that someone happens to be wandering by this blog, consider yourself spurred on.

Speaking or RPN, if you like RPN and weren't aware of the dc calculator available in most UNIX environments, consider yourself enlightened. Although honestly I use bc more than dc because dc's interface is a bit arcane. Like not printing the top of the stack automatically, and that you have to use _ for negative numbers instead of -. bc is not RPN, but that's less annoying (but still annoying) when you have a full keyboard and screen, and readline support. I've occasionally seen other RPN calculators both in terminal and GUI. As far as GUI goes, as you may have read here before I'm partial to Apple's Calculator included in OS X. Its only flaw is not being able to see more of the stack at a time. I've not yet come across a terminal one to replace bc, which is what I'd prefer. Let me know if you've come across one. Someday I may hack one up. If I do I'll include unit conversions (with units in the background) and math functions with the same names as the C math library.

I ported my calculator to javascript and an HTML form, which you can find at http://hans.fugal.net/sourdough/calculator.html. Happy baking!