Creamy & Smooth Oat Milk

 This recipe is a variation on ones I found online.  I think it has a much nicer mouthfeel compared to other recipes, because in addition to the oats it contains fat of some kind, like butter or coconut oil (I actually like the coconut oil better).  It also is cooked slightly.  My recipe also adds a small amount of salt and sugar, but they are optional (but recommended).

Creamy Oat Milk

Makes approximately 1 quart of oat milk

2/3C rolled oats.  Not quick (pre-cooked) oats.

1/2 tsp salt

1 tsp sugar

1/2T butter or coconut oil.  They don't have to be in liquid form.

4C water, divided

Optional flavorings:  vanilla or almond extract.  I haven't tried cocoa powder, it probably would require more sugar to balance the bitterness contributed by the cocoa.  Dutch Process cocoa would be less bitter.  These flavors should be added after the oat puree is strained.

1.  Put the oats in a blender.  Add 2 cups water at room temperature, cover with the blender lid and allow to soak for 30 minutes.

2.  Blend on high for 30-60 seconds.  Strain into a bowl with a fine-mesh strainer, using the back of a large spoon to gently press down on the pulp.

3.  Add the remaining water, salt, sugar and fat to the bowl.

4.  Heat on High in a microwave oven, long enough to raise the temperature of the oat milk to 140F.  See Note below.  This step gelatinizes the starch, which gets rid of the gritty mouthfeel.

5.  Use a whisk to blend in the now-liquid fat.  The idea here is that the fat will form something like a roux where the fat globules are surrounded by starch so they will form a relatively stable emulsion.

Higher cooking temperature and more fat might make something closer to cream rather than milk, but if you over-do it you will likely end up with something that is more like pudding instead of milk.

Pour into a 1 quart jar and store in your refrigerator until ready to use.  Shake well before using.  Keeps for about 1 week.

NOTE  Our microwave oven takes about 5 minutes to heat the oat milk to 140F, but ours is an older, lower-powered one.  To check your microwave, place 4 cups of tap water in a bowl and "nuke" it for 4 minutes.  Stir to equalize the temperature and measure the temperature of the water.  If the temperature is higher than 145F, decrease the time by 30 seconds and try again.  If lower than 140F, increase the time by 30 seconds and evaluate the result.  You want to run enough room-temperature water in the bowl so it doesn't affect the result for each trial run.  The final test is to measure the temperature of a batch of your oat milk, since the actual volume of water will be slightly less than 4 cups.

Once you get the temperature to 140-145F you have characterized your microwave.  Make note of the time for the next time you make this recipe.

Low-E Materials for Solar Water Heaters

 As part of a liquid desiccant-based A/C system, an inexpensive heat source is needed to regenerate the liquid desiccant (LD).  One of the most-common approaches, used by Tech Ingredients for their exerimental systems, is a solar water heater.  In turn their design is based on one that Desertsun02 came up with, but they have a nice addition, which is to use low-E glass instead of plain glass.  The idea is to increase the efficiency by reflecting the longwave IR that's generated by the hot interior of the water heater back toward the water tubes -- rather than escaping out of the heater.

The problem is that low-e glass isn't all that easy to come by, at least in the searching that I have done.  Most vendors are selling complete low-e window units, while the best source for the odd piece of low-e glass is a custom house.

But it turns out that you can get low-e plastic film to put on a standard window, and it's not all that expensive, either.  So far, so good:  but there are DIFFERENT types of low-e films.  The most common is a film with a thin reflective layer of aluminum, which reflects both visible and IR.  Not useful for a solar water heater.  There is a class of so-called "transparent" low-e films that are available, which might be suitable.  Looking at reviews for these films indicates that the biggest challenge is applying the film without wrinkles or bubbles.  I suspect that the biggest challenge is that the film is being applied to a window that's already installed.  In my case I can lay the "substrate" glass flat, which should make it easier to properly apply the film.

The other potential issue is that the highest-efficiency LD based system requires that the LD be heated to at least 60C to regenerate it.  The film will be exposed to this temperature (via convection on the interior of the enclosure).   How long will it hold up??  Hard to say, since my application is far different from the intended purpose.

Addendum to the DIY A/C addendum

 It's been awhile but after reading my post regarding the use of an indirect-cooled evaporative cooler that's running a pseudo M-cycle scheme, I thought it good to mention that if the incoming water is below the ambient dew point (house interior), at least SOME parts of the system will likely have water condensation on them.  Hoses, any parts of the heat exchanger that isn't getting much, if any, air flow around it, etc.

One reason for re-visiting the subject is, of course, our current heat wave.  It got to 105 yesterday, and probably will get close to that today.  The day after it will "just" get up to 100.

The current outside air is at 77F/25C and 64% relative humidity.  According to my trusty psychrometric chart the wet bulb temperature is about 20C (68F) and the dewpoint is about 17.5C(~64F).  I have observed that the current air conditions are such that the wet bulb and dewpoint temperatures remain the same, as the air heats up.  That means that the humidity ratio (water/air mass) remains the same -- everything is so dry that there's little evaporation occurring!