Homestead Happiness, February Week 3

We're still fine-tuning some of the experimental details on our eggshell leavening, but it was otherwise a productive week around the homestead (thanks to some unseasonably warm weather!).  Here's what made us happy this week.

We got another batch of wine started, this one from frozen black raspberries.  They had been in the freezer since July of 2004!  They say a fine wine improves with age, guess we'll find out if that applies to aging before fermentation, too.  At least, the berries still tasted good!  Also, starting the wine meant Jake could clean up the mess that the berries made in the fridge while they were thawing.  That made Katie extra happy.

Outside, highs in the 50s and 60s (°F) made for happy playing in the dirt, including playing musical berries.  We transplanted dormant strawberries out to the garden where we can protect them with the motion detector sprinklers, and dormant raspberries to the place vacated by the strawberries since they weren't thriving in their original location.  Also, 'Musical Berries' is going to be the name of our new family band.

Also on the yard work list was chopping out the remaining stump from the tree of heaven, filling the hole with dirt, and planting another tree in it's place.  Some of the old stump pieces had termites, which the chickens liked a lot.  In fact, they were willing to brave a battlefield of flying wood chips to get to them, and with 100% survival rate.  We've got ninja chickens! (Never mind, we're going to call our band 'Ninja Chickens.')

In the process of our eggshell leavening experiments, we also made a big pile of wood ashes, which we'll use in a future set of leavening experiments.  The connection between these two will become apparent in the near future.

The rhubarb is alive!

The chives are also alive!  It's always nice to know the plants are starting to think springly thoughts, too.  The weather, on the other hand, is very ambivalent--after highs in the 60s on Saturday, we got a nice blanket of snow last night!

The chickens are also revving up their egg production--four eggs in four of the last five days.  Keep up the good work, ladies!

What made your homestead happy this week?

Homemade Potato Starch

There are lots of uses for starch around the homestead: thickening stew or pie filling, making gravy, making edible glue (Katie says, "well, if you're going to eat it anyway..."), making cosmetics, powdering wigs, and so on.  Clearly, we need a way to make some homemade starch.  The tricky part is, most commercial starch comes from tropical plants like arrowroot or cassava, or from hard-to-process grains like corn, wheat, or rice.  Except potato starch.  Potato starch is made from something we can grow and process without too much trouble.  Ready...go!

The first step is to figure out how much starch we can expect to get out of our taters, so we can calculate a yield later on.  Since starch is denser than the rest of the potato, a potato's density is generally proportional to the starch content.  Using the displacement method...

...we found that our potatoes are 13.3% starch, averaged over five potatoes.  Data for the graph on the left came from here.

The next step is to get that starch out of the potato cells.  The starch is trapped inside the cells like a medieval princess in a dragon's lair , waiting to be eaten by the dragon in the spring (if princesses looked like oblong globules piled inside a vaguely hexagonal prism).  And we get to be the knight in shining armor.  (Photo Credit: "Potato Starch" by Philippa Uwins (CC BY-SA 3.0), via Wikimedia Commons)

 Fortunately, we wield the mighty Sword of KitchenAid

A few minutes later, the dragon is nearly defeated.  Now we just need to rescue the starch princess.

We do that by flushing the potato pulp with water and using the ol' t-shirt filter and squeeze technique.

We mix the pulp with water and squeeze out the milky-colored liquid three or four times until the water looks fairly clear (it looks white at first because it's carrying the starch granules with it).  We can keep rinsing and squeezing beyond that if we want, but then we begin to wander into the Land of Diminishing Returns.

Now we're left with the potato pulp (left) and water/potato juice/starch (right).

Pouring the water into something with a higher aspect ratio will help in the next step when we decant the juice.  The white layer on the bottom is the starch princess, which settles out on standing for a few minutes.

While the starch is settling out, we take the potato pulp, mix it with a chopped onion, egg, salt, pepper, garlic powder, and rosemary...

...and fry up some potato pancakes! (Or dragon burgers, whichever you prefer.)  Dragons: thank you for meddling in the affairs of homesteaders, for you are crunchy and good with ketchup.

Once it looks like no more starch is settling out of the liquid, we carefully pour the liquid into a pitcher, leaving a solid layer of starch behind. (If you splash and swirl the liquid while pouring, some of the starch will come with.)

We scrape the starch out onto a dehydrator tray with a fruit leather insert. Now we just have to drive off most of the water.  We want to not go to very high temperatures in this step, since the starch will start to gel around 64 °C (147 °F).  So we'll stick to the food dehydrator, like Mrs. Volfie suggests. 

Holy non-Newtonian fluids, Batman! One cool thing about concentrated starch-water mixtures it that they're shear-thickening.  That is, apply a force to them, and they act like solids.  Let them sit there, and they act like liquids.  Kind of a pain when scraping the starch out of the jars, but if you spill any on the counter, just grab that drop with your fingers and pick it right up!  You can also watch the solid transform back into a liquid, which is kind of apparent in this picture.

If some of the juice comes with the starch, it will form dark-colored parts when it dries.  But it won't make much of a difference in the final product.

Once it's powdered up, it still looks pretty white, like starch is supposed to.  Our final yield was 131 g starch from 2272 g (5 lbs) of potatoes.  At 13.3% starch, that many potatoes should have given us 302 g starch, so we ended up with about 43% yield, based on the theoretical maximum.  Industrial processes give about 90% yield or more, so we're not quite there.  But industrial processes also don't give potato pancakes as a byproduct, so we've got that going for us.

If you search online for what to do with the juice, you'll find a plethora of sites with unsubstantiated claims about the health benefits of potato juice (although there may be some merit, if you dig deep enough).  They also usually recommend blending the potato juice with other components, such as lemon juice and honey, to mask the flavor.  It's not that bad, but we haven't found a reasonable combination of lemon juice, honey, and potato juice that render it satisfying.  It's better with more strongly-flavored ingredients, like chai tea concentrate and hard liquor.

How do you make starch on your homestead?  Let us know in the comments section below!

Historical Lye Making, Part 2

On Thursday, we posted about historical methods to drip lye and some of the chemistry associated with it.  Today, we wanted to talk about measuring the strength of the lye to check if it's concentrated enough for making soap.  In the olden days, that was often done with some sort of density test, either by floating an egg or potato, or matching the density of the lye solution with a saturated table salt solution (sodium chloride, NaCl).  An egg has a density of 1.03-1.1 g/mL, and a saturated NaCl solution is a little more precise at right around 1.2 g/mL, but in our soap calculations, we normally use a solution that is 1.3 g/mL, according to density-sodium hydroxide concentration correlations.  One initial conclusion from that is that old-time soap makers probably used less concentrated lye solutions.  Similarly, older soap recipes often call for cooking the lye water and fat together (i.e., hot process soaps), which probably boils off a lot of the extra water.

For modern homesteaders, who might have a scale and measuring cup handy, it would be much more precise just to measure the density of the lye solution directly.  (A graduated cylinder would make this calculation--and other density calculations you might want to do--more precise, but a measuring cup, used judiciously, should be good enough.

Another technique is to use a pH indicator and either dilute a small (representative) portion of the lye water or titrate it with an acid (such as vinegar) to find the strength of it.  The pH indicator would also be useful during the soapmaking process to check the progress of the saponification reaction.

Let's take a look at each of those techniques in more detail.

To make soap, we normally use a ratio of something like 2.89 oz NaOH to 7.87 oz water, which works out to about 26.9 wt% NaOH.  According to the above calculator, that should give us a solution density of 1.29 g/mL.  (The analogous numbers for KOH lye would be 4.06 oz KOH to the same amount of water, giving 34.0 wt% KOH, and a density of 1.33 g/mL.)  If we take an egg density of 1.1 g/mL, we can calculate the amount of water that should be displaced by the egg if we know the volume of it.

A typical large egg has a mass of 57 g, corresponding to a volume of 51.8 mL.  Buoyancy dictates that the egg should displace 57 g of the lye solution, which will correspond to a volume less than 51.8 mL if the lye solution is more dense than the egg (which it should be if the egg is floating). As an approximation, we can find an equation for an egg and make a graph to see how much of the egg should be above the water for a quarter-sized interface.

The egg equation came from here, but we normalized it to match the dimensions of an actual egg.  We assumed that an egg was sufficiently symmetrical to use a 2-D projection and calculate areas instead of using a 3-D model and calculating volumes.  In reality, the egg will sit with the skinny end slightly lower in the water since the air pocket is toward the flatter end.  In any case, leaving an area the size of a quarter above the surface would require a lye density of 1.13 g/mL, which is considerably less dense than our standard recipe, which has a density closer to 1.3 g/mL.  If the egg were a little less dense (toward the 1.03 g/mL end), it would sit higher.  As a point of reference, a potato has a density near 1.09 g/mL, in the same range as an egg.

This is a real egg in our standard lye solution (using NaOH).  The solution is yellow because we were testing pH indicators with it (described below).  The real egg looks not too far off of the graphical one, but there are more precise ways to test the lye's strength. 

For example, using data found here (and their related NaOH calculator), we can make a correlation, measure the density of the lye directly, and use the correlation to calculate the concentration.  It would help to have a digital scale and a graduated cylinder, but you can probably get at least as close as the egg/potato method with an old spring-loaded scale and a measuring cup.  We dripped a small batch of lye recently and were doing tests with it, but accidentally spilled it in the kitchen sink before we could test this method.  For lye dripped from ashes, use the KOH equation.  Note that if our solution density is 1.3 g/mL, our lye concentration (as KOH) is about 34 wt%, or 5.2 molar.  This density method will be our favorite lye strength test going forward.

Another way to test the strength is with a pH indicator.  One natural pH indicator is cabbage juice, which contains anthocyanidin pigments.  (As an aside, we noticed similar color changes in elderberry juice and wondered why; elderberries have a similar set of pigments.)  These pigments change structure as the pH of a solution changes, with each structure having a different color.  See here for more info.

The pigment structures of the cabbage anthocyanidins look something like this, with the different colors as shown.  Part of the reason the change from red to purple happens over such a wide pH range is the colorless intermediate.  Similarly, the yellow compound starts to form at pH > 8, but doesn't become the dominant form of the molecule until much higher pH (the presence of both yellow and blue make the solution green, kind of like a Ziploc bag).  The "R" groups are glucosides (i.e. substituted glucose molecules).  Sources for this figure came from here, here, and here.  If you took note of the concentrations above (i.e., that our standard soap recipe calls for 5.2 molar lye) and you are familiar with the pH scale, you might realize that there's a bit of a problem here.  That is, our lye should be at pH 14.7, but our indicator will be yellow at every pH > 11.

Fortunately, we can dilute a small, representative portion of the lye to bring it into the pH range where the indicator is effective.  On the far left in this picture is an undiluted lye solution we dripped from some wood ashes a few weeks back; it's yellow, which means the pH is at least 11.  Since pH is measured on a log scale, diluting by a factor of 10 (conveniently 1 teaspoon solution plus three tablespoons water) should decrease the solution pH by one unit (assuming the water is actually neutral).  On the first dilution, the solution is already green!  That means the undiluted solution was not much over pH 11.  The further dilutions (using one teaspoon of the first dilution plus three tablespoons water, etc.) are consistent with that conclusion, looking similar to pH 9 and pH 7-8  solutions above.  The upshot of this technique is basically (heh) that if the lye is concentrated enough for soapmaking, it should take at least four 1:10 dilution steps to show a color other than yellow.  Alternatively, that means that we should concentrate our lye solution by a factor of 1000 before using it to make soap.  Unfortunately, we only made around a quart to begin with, so we'll only be left with a few drops at the end--not enough to do much with (even dissolve a feather, which was another test of lye strength we were going to try).

Another approach would be to titrate the lye with an acid, and figure out how much acid we needed to observe a color change.  Maybe that will be the subject of a future post.

Guess we'll just have to dry it down with waste heat from the oven (after baking bread or something) and store it in a jar until we can make some more!

Also, in case you're interested, here's how we made the pH indicator solution.  We chopped about a third of a cabbage to give around four cups chopped cabbage.

Then we poured about two cups boiling water onto the cabbage and let it steep for about two hours.

Then we strained out the cabbage (and made coleslaw!), leaving this dark purple-colored liquid.  We add about a teaspoon of this 'cabbage tea' to a cup of liquid to test the pH. It's a little-known fact that a hot jar of this liquid was the inspiration for both the band name 'Deep Purple' and their hit single 'Smoke on the Water.'  (Don't bother looking that up.)

Have you dripped lye from wood ashes?  What did you use it for?  How did you test the strength?  Let us know in the comments section below!

Coconut Oil Replacement for Temperate Climates

It seems that a lot of recipes for homemade hygiene products call for coconut oil as a primary ingredient.  And why not?  Coconut oil is touted as having numerous benefits, which may or may not be legit. (Many of the benefits may be topical rather than dietary.)  We're not much into beauty products, but occasionally we discover a need for some type of 'cosmetic' product, such as deodorant for when someone we actually like invites us to an event in the public sphere.  In the past, we have incorporated coconut oil into some of our homemade hygiene items, mainly as a high-melting binder for something like deodorant.  However, we've found two problems with this situation.  First, the coconut oil, although higher-melting than many other oils, sometimes melts in the summer heat.  Second, we have no intention of living in the coconut's natural habitat (coastal areas within ~26° latitude of the equator), which means it would be very difficult to produce our own coconut oil on the homestead.

However, we do (or more precisely, will) have the capability to produce beeswax and vegetable oils (e.g., canola or sunflower oil), which we hypothesized we might be able to combine in certain proportions to produce a mixed-lipid substance with a tunable melting point.  The first thing we had to do was build something to measure the melting points.  Oh boy, a project!

We wanted to use a spare piece of leftover metal from the 90° electrical conduit punch-out elbows we used for the row cover we built last fall, but the Home Depot spec sheet said the pieces were either cast zinc or galvanized steel. We were a little nervous about heating zinc (it turns out it would have been fine for this application anyway), but when we held the pieces, they sure didn't feel dense enough to be zinc or steel (which have densities of 7.2 and 7.8 g/cm³, respectively).  We suspected they might be aluminum, so we converted an empty spice jar into a makeshift graduated cylinder (sort of like a really nerdy MacGyver), then used the old displacement principle to calculate a density of about 2.7 g/cm³--suspiciously close to that of aluminum.  No zinc fume worries, and good thermal conductivity--yay, science! (And Home Depot shoppers be warned...)

Then we built a little contraption out of scrap wood to turn our aluminum piece and our wood burning tool into a melting point apparatus.  She ain't purdy, but she sure is sturdy!

We drilled a partial hole in the center of the bottom in which to nest the wood burner, and two holes equidistant from the center: one for a small piece of whatever solid we're melting and one for a thermocouple or thermometer.   This setup heats surprisingly quickly, so we had to serve as our own PID controller by plugging in and unplugging the wood burner.  It would be way easier to add a potentiometer between the wood burner and the wall outlet (something like this guy did), if we had one on hand and wanted to precisely control the heating rate.

The next step is to put a small chunk of the wax or wax/oil mixture in the one hole, hold the thermocouple in the other hole, and heat 'er up!  Keep heating until...

....the wax melts!  We got 142 °F as the melting point for the pure beeswax, which is pretty close to the normal range.  The aluminum plate cools down pretty quickly, so we can record the temperature at which it re-solidifies also, and do multiple melts to get an average.  (Since we know the approximate melting point from the first melt, we can unplug the wood burner sooner in subsequent replicates to approach the melting point more slowly--maybe even as slow as a real melting point apparatus would!)

With the instrument and methodology validated, we can finally pursue our goal of finding a beeswax/oil blend with the melting temperature we want.  We mixed up combinations of 80%, 60%, 40%, and 20% beeswax in canola oil (by volume) as our standards.

Then we made sure they were good and melted in the microwave.  We stirred the melt to mix everything well, then set them outside to freeze.  If the air outside is going to be cold, we might as well make use of it!

The 20-80% beeswax standards all had a pretty high melting point (e.g., the 20% mix melted at 118 °F), so we added a 5% beeswax mix to the curve.  It looked kind of like runny Vaseline, and seemed to cross over to the liquid side around 70 °F.  That's lower than the melting temperature of coconut oil (which we measured at 79 °F, compared to an internet value of 77 °F), and is probably too soft for making deodorant.  The 20% mix seems like it might be about right.

Here's the data all together.  The point at the far left (pure canola oil) is from here since the air outside wasn't quite cold enough to freeze it (nor was our freezer, for some reason).  Naturally, the curve would look different if other oils were added into the mix, but we'd wager that oils with a similar fatty acid profile to canola oil would give similar results.  The line is a fit to the equation shown, which has no physical meaning, as far as we know, but seems to fit the data well.  (Hooray for empiricism!)  Physical chemistry students: you might be able to publish a paper on the theory behind it.

Have you mixed beeswax with other oils for your own homestead hygiene?  What's your favorite combination?  Let us know in the comments section below!

Turning Grease and Trimmings into Lard, Cracklins, and Soap

NOTE: This is a long post and is way too technical at times.  We should have probably broken it up into two posts--how to render lard/tallow and then how to make soap out of it.  But we wanted to keep the whole process in the same place, as a single reference.  Hopefully some of our readers will appreciate the thoroughness.  If you are not one of those readers, apologies in advance.

Last weekend, we wrote about saving our bread crumbs in the freezer to turn into schnitzel.  We do a similar thing with our meat trimmings and leftover frying grease, and bacon drippings.  Except we don't make schnitzel out of them.  We make cracklins and soap.  Very little goes to waste, and if we had dogs, none of it would!  It's a many-step process, so let's get started.

We started collecting meat trimmings and leftover grease in canning jars in the freezer.  When we decided we had enough for a good batch of soap (which was this weekend), we thawed them out.

We sped up the thawing process in the microwave.

After two minutes or so, the trimmings are liquidy enough to scoop out of the jars and into a single bowl.

We added a few cups of water to the mix.  The idea is to get everything liquid, and impurities in the fat will settle down into the water layer.  Another five minutes in the microwave and a lot of the fat is melted, but a good portion of the trimmings are still solid.  That's ok for now, it just means that they had a lot of either very high-melting fats or non-fatty material.

A second five-minute stint melts quite a bit more of the fat, and with that, we'll set it in the fridge and let it cool down.  With the light shining from the top, it's easy to see that most of the impurities have gone into the water layer and the fat left on top is nice and clear.  Yay, we're rendering!

After a few hours the fat is what amateur scientists might call 'recrystallized'.  It's pretty white, but there are still some brown things in the fat. 

So we'll scoop most of the fat into another bowl (left) and discard the water (gasp!).  If we had a dog, we'd give it the water as a treat.

We switched the fat back to the other bowl, added more water to the scooped out fat and microwave it again for 5-10 minutes.

More of it is melting, and some solid specks are visible at the bottom of the bowl.

Then we take it out of the microwave and scoop out any big pieces of solids that haven't melted yet.  These must be things mostly not fat (or really high-melting fat).

Now we've got one bowl of slightly-less-fatty solids and one bowl of clean fat on top of dirty meat-water.  The second bowl goes back into the fridge to solidify the fat again.  After that, we'll get rid of another batch of water.  What a lucky imaginary dog we have!

The first bowl goes into the frying pan to make cracklins!

We let them cook down for a few hours.  Some additional fat will melt, and the rest will fry down into a tasty toasty batch of delicious.  Some folks recommend not making cracklins in the indoor kitchen because the whole house will smell like cracklins and they will splatter oil everywhere.  We're not sure why the first reason is bad, but we went with a low heat and didn't have much splattering or odor.

Here they are cooked down, stewing in a delicious bath of their own making.

We drained off the fat into the other bowl and stirred it up a little bit to make sure any non-fat parts of the cracklin grease get extracted into the water layer.  (If upon solidifying, impurities in the fat layer are still visible, you can do another step of removing the water, adding clean water, melting everything again, and removing the water.  Hopefully your dog has been really good.)  Then we seasoned the cracklins (a few sprinkles each of salt, pepper, garlic powder, cayenne pepper, and Tabasco sauce), then took the spoon and broke up the cracklins into small pieces (after trying a few, of course).  We use the pieces like bacon bits.  We're eating ours on chili this week. They are not healthy, but they are good.   Everything in moderation.  Mmmmm.

We'll need to know the weight of our purified grease, so we're going to start by weighing our now-empty bowl.

...And now with the fat in it.  Some folks use this grease (mostly lard for us) as a foodstuff largely equivalent to modern-day vegetable shortening (after it solidifies).  Lard has gotten a bad rap as being unhealthy, but actually has a healthier lipid profile (less saturated and more unsaturated fat) and lower cholesterol than butter.  (According to Google anyway.  How does Google know this stuff?)  It's certainly not a health food, but to dismiss it as less healthy than shortening or butter isn't fair, either.  (Keep in mind that lard rendered this way is likely better than store-bought lard, which has often been hydrogenated just like shortening.)  Anyway, we've got more of a need for soap than pie crusts for the time being, so we're going to turn our lard into soap.  The following process is what's described as cold-process soap.

At this point it's probably a good idea to review the soap-making process.

<chemistry-dense section>
Lipids such as vegetable oils, beef tallow, and lard, are made up of triglycerides, or TGs.  TGs are made up of a glycerol 'backbone' and three fatty acid tails (the tails are often abbreviated R or R' or R'' by lazy organic chemists).  Saponification breaks the tails off the glycerol backbone using a basic reagent (normally NaOH or KOH), which forms glycerol and a fatty acid sodium (or potassium) salt (i.e., soap).  Each type of lipid (and even the same type of lipid from different sources!) has a different fatty acid profile in its makeup (some of the tails will be longer or shorter, or have different numbers of double bonds (which makes them 'unsaturated').  Because the the oil and base react on a number basis and not on a mass basis, therefore, an ounce of different oils will require different amounts of base to react fully into soap.  This feature is reflected in a characteristic called the saponification number, or SAP number for short, which is formally defined as the mass of potassium hydroxide (KOH) in milligrams (mg) required to fully saponify one gram of a given oil.  These numbers will typically be in the 100-200 range.  Many times, however, SAP numbers are reported as 'grams per gram' or 'ounces per ounce', which are different by a factor of 1000 (they'll be in the 0.100 to 0.200 range).  SAP numbers are tabulated in many places, including online (of course), and many tables give a range, or give values that differ from other tables because of the inherent variability of an oil type's chemistry.
</chemistry-dense section>

An example of how a SAP number is calculated from an oil's composition is given in the spreadsheet linked here.  The spreadsheet also shows how to use the SAP number to make a soap recipe for a given fat composition.

Anyway, we estimated that our fat was about 70% lard, 15% beef/venison tallow, and 15% olive oil, and we had 21 oz. total.  That means we had 14.7 oz. lard and 3.15 oz. each of tallow and olive oil.  The SAP values for those are 0.138, 0.140, and 0.134 for NaOH, respectively (it would be different for KOH), which works out to 2.89 oz. of lye to fully saponify the fats (multiply the amount of fat by the corresponding SAP value and add them together).  Normally, a 'lye discount' is used to leave a little bit of the fat intact.  That makes the soap less harsh.  We took a lye discount of 9.5% (requiring 2.62 oz. lye), which is pretty high.  But we know that the cooking process itself will start to break up the triglycerides, and used cooking oil will often contain ~5% free fatty acids (i.e. material that doesn't need lye to become soap).  So we eased off on the lye to account for those as well.

Where do we get our lye from?  We found what we were looking for in a certain type of drain cleaner, but we had to be careful that it says 100% lye or 100% sodium hydroxide on it and is white in color.  Other ingredients might interfere with the saponification, and might be dangerous to clean yourself with.  (Unless you're a drain pipe.  If you can read this, you're not a drain pipe.)  Soapmaking and biodiesel sites can also be good resources for where to find good-purity lye (or make your own!).  It's important to have a good soap recipe.  There are plenty of good links on the internets, but we like a ratio of about 6 oz. water per 16 oz. fat, and lye according to the saponification (SAP) number, minus the lye discount.  Also, for our lye, which is in granulated form, we found that one ounce of the granules equals 1.814 tablespoons (by weighing a half cup and dividing by eight).  The small amounts are easier to measure by volume in a tablespoon than by weight on our mechanical kitchen scale.  The density used to be less than that--this lye is a couple years old and lye in general is hygroscopic, which means it will take on water from the atmosphere.  That can affect your measurements, so make sure to keep your lye tightly sealed.  In effect, we're actually taking a larger lye discount than we calculated above because some of the 'lye' we're weighing out is really water.  But in our case the water content hasn't changed too much, so our calculation will still work.  So our final recipe is 21 oz. rendered fat, ~1 cup water, and 2.62 oz lye.  SAFETY NOTE: All steps with lye should be done wearing rubber gloves and goggles!  If any lye or lye solution gets on your skin, rinse it off right away with lots of water.  Don't let any get in your eyes.  That would be very bad.  If it does, flush with lots and lots of water and get to a doctor.

We mixed the lye and water.  Add lye to water, not the other way around, or the first water you add could get superheated and pop, sending caustic ooze flying around the kitchen.  Caustic ooze makes Katie unhappy, especially in the kitchen.

It will get hot.  Normally hotter than this.

When it cools down a little (to ~110 °F or so), we added the lye solution to the fats and stir.

We keep stirring until the soap 'traces.'  That means the spoon stirring through the liquid will leave a visible trace (or something like that).  Anyway, when it's the consistency of warm molasses, it's traced.  In chemistry terms, that means the saponification reaction has gone far enough that the fat and the water we mixed together won't phase-separate anymore, and we can pour it into our soap mold. (Oh yah...we need to build one of those...)  Before we do that, though, we add any other ingredients we might be thinking about--little pumice scrubber things, girly herbal things, or something to make the soap lather better, because standard soap molecules by themselves don't make much for bubbles.  Castor oil is commonly added to increase lather, but we didn't have any on hand.  Why does castor oil work well?  Because the fatty acid chains have hydroxyl groups on them, which interfere with water's surface tension.  (A bubble's film needs an optimal viscosity-to-surface tension ratio and a slow water evaporation rate to be stable, and the hydroxyl groups in castor oil move the soapy water's properties closer to that optimum, mainly by reducing water's surface tension via disruption of it's hydrogen bonding network.)  So, what if we added something else with hydroxyl groups?  Like sugar or honey--it will work!  We added about 1.5 tablespoons of honey at trace.  Katie likes bubbles.

A glass dish like this functions ok as a makeshift soap mold.  This will be the final shape from which we cut our soap bars, so we have to make sure it's nice and smooth.

That's better.

After sitting for a few days, and it will become nice and solid.  After a week or so, we'll take it out of the pan (hopefully in one piece), and cut it into bars.  It will need to cure for another month or two before it will make good soap.

UPDATE 10/4/2013: We cut it into bars and it's now curing.  Here's some pictures:

After a few days, the soap should be solid enough to take out of the mold and cut into bars.  We used a flipper/spatula thing (the device used for flipping hamburgers or removing cookies from a cookie sheet post-bake).  We got lucky this time and the soap all came out in one big, chic-looking piece.

Then we cut it into bars and spread it out on a plate so it will cure faster.  Also, to teach a lesson to any hungry burglars thinking we have a plate of cheesecake bars or something on top of the fridge.  Don't forget to brand the bars, if you're into that kind of thing.  We'll leave it like this for 6+ weeks, though others say it would be fine to use sooner.

Then we washed the soap mold.  Guess what!  We didn't even need to add soap!  That must be the cleanest dish ever.

Do you have other soap-making tricks?  Have you ever done it with wood ashes as your lye source?  What else do you do with scraps from your meat-trimming operations?  Let us know in the comments section below!