Stefan Joest wrote with many questions about Brix: [snip]
> For the Brix there is some calculation done with the refractive index
> which I couldn't find out. But the Brix is in principle the same as the
> refractive index.
True. Brix is also defined as the number of pounds of solids in 100 pounds
of fresh plant sap or juice. I assume you would think of it as grams per
liter. The hydrometer scaling peculiar to Brix was devised by your
countryman, Professor A.F.W. Brix.
> So this all means:
> - you have to have a liquid. A solid medium won't do
True. There is a minor exception. You can take a thin slice (about 1/16th
inch) of something and lay it on the prism. It will give a direct reading.
Some farmers prefer this method for testing Irish (white) potatoes.
> - the liquid has to be transparent - milk won't work
False. Ordinary store milk is about 10-11 Brix. The best milk I've seen
was 20 Brix and tasted mar-ve-lus. Pasteurization won't change the Brix
but, as I expect you know, it devastates the taste.
> - the liquid shouldn't be too dark else it is impossible to send a light
> beam through it. Good refractometers have a very strong light bulb to
> measure even dark liquids.
Only one model of hand refractometer has a battery powered illuminator. All
the others I've seen use ambient light. The sap of very rich greens, such
as kale, will cause you to turn toward a bright light.
> The prices in my catalogue range from 500 DM to 18,000 DM and I think
> the dollar is around 1.80 DM, so calculate yourself...
Sounds like someone wants to rip you off. I posted a much better price
(USD$130) for a decent instrument. Another list member mentioned a cheaper
price (USD$80), but I expect that was a model that requires manual
temperature compensation. Either price is a bargain for something that lets
you laugh at the b.s. put out as "Food Nutrient Composition Tables."
> While the full scale seems to be 0..90 Brix, most refractometers can
> measure only one third of that. The catalogue lists refractometers
> for 0..32 Brix, 33..58 Brix etc.
> One refractometer (price 1000 DM) was a full range one.
Full-range is not necessarily desirable for food selection or growing. 0-32
or 0-30 Brix models are calibrated to .1 or .2 Brix and extremely accurate.
0-90 Brix is, of necessity, scaled less because of the difficulty of
etching the screen. I haven't studied the electronic read-out bench models,
but they may give full-scale accuracy down to .001 Brix.
> Concerning measuring the quality of foods a bunch of questions arise:
> - obviously the food must be juiced before measuring and the juice must
> be filtered to make it transparent. How to measure coconut flesh and
> other seeds/nuts then? Does one have to make oil of them? (Complica-
> ted - needs an oil mill)
Brix is applicable to fresh-squeezed fruit or vegetable juices. Admitedly,
it can sometimes be tough to get a drop, such as from a leaf. Fruits are
rarely a problem, but I use a garlic press for vegetables. I also have a
pair of modified pliers (cost USD$20) that are handy for testing leaves.
Dr. Reams based his coconut value on the milk, rather than the meat. This
seems reasonable to me and a taste panel will confirm he did the right
thing.
> - why should "more Brix" equal "better quality"? Just the fact, that
> there are more molecules present in the juice which give a higher re-
> fractive index, doesn't say if they are "good" molecules.
There are many ways of determining quality. One way that you might be
familiar with is to raise animals and track the feed they consumed. Those
that develop full genetic potential, are able to work hard, and that can
reproduce are considered "healthy." By definition, I would consider their
feed healthy. My experience has been that animals fed high Brix feeds
(alfalfa, grasses, etc.) thrive. Conversely, those fed low Brix feeds tend
to languish and require unending veterinarian care.
Another method of determining quality is to visually correlate a plant's
ability to remain free from pathogens and parasites (insects) vis a vis its
Brix. No problem there: when the Brix reaches the "excellent" levels on the
charts I have, the bugs and disease go away. Some reading this will extend
their thinking to understand that a plant able to withstand attack will
possibly confer health to a human consuming it.
Another method of determining quality is to chemically test for various
plant developed minerals, vitamins, amino acids, proteins, taste factors,
whatever. Well, higher Brix means more of whatever it is you're worried
about. Dr. Reams, who extended the concept from grapes to citrus and other
plants, ran an agricultural lab. He constructed the charts based on what he
found via lab analysis.
A key point in Dr. Reams studies was that higher Brix led to more decay and
rot resistance. Again, most people can easily accept that food that resists
rot is probably better for them than food subject to quick decay.
I'm sure there are other means of defining "quality." One way would be for
you to employ a taste panel. Brix has been *right on* for every taste panel
I've convened. BTW, I trust children more than adults for such critical
work. Adults confuse their mental process sometimes by thinking it is "bad"
to like sweet. I assume that comes from domineering parents. Perhaps it
comes from "take your [bitter] medicine: it's good for you."
> Couldn't an artificial fertilizer give the same result?
Nope. You've hit on a major reason mainline agriculture scoffs at the
refractometer. Applying salt NPK fertilizers to plants causes them to
ingest more water to reach equilibrium, the same as if you ate salt. This
lowers the Brix and is an everlasting consternation to commercial chemical
farming. In addition, the toxic technology makers aren't too interested in
growing food that doesn't need artificial protection from insects and
disease.
> - what about denatured molecules which yield a high Brix? This food
> would have a high Brix then but would be (partially) denatured
See above. Brix was devised to measure fresh squeezed plant juices. I have
absolutely no knowledge of what denatured food would test. I can tell you
that brewing, whether for beer, wine, or whiskey, changes Brix values
around, but I don't know the mechanics or ultimate results.
> - if the Brix originally was for grapes, I would understand it. The
> vinters are hunting for more sugar contents and more sugar gives a
> higher Brix.
Sugar is a component of Brix. Brix is much more than sugar. As I've
mentioned before, to demonstrate this, simply put a spoonful of sugar in a
glass of fresh juice. Yes, it will raise the apparent Brix, but it does
diddly for the taste. Artificially sweetened 12 Brix apple juice tastes
like it has been watered down. 18 Brix apple juice has a taste that makes
you want to write home to momma. If your statement was true, the vintners
could save a lot of money by buying cheap cane sugar.
> But can one generalize this to other foods?
No generalization intended: the charts cover the common North American
fruits and vegetables. Much of the Brix work is based on rock solid
results, not theory studies. A little checking at the store, or in one's
garden, quickly reveals the same variety of plant can have a widely varying
Brix. Daring, or caring, to put samples of the tested produce in your mouth
can bring a look of enlightenment to your eyes. As the Brix goes up, so
does the taste.Charts would have to be constructed should folks want to use
the method on unfamiliar (to N.A.) local produce. For instance, the first
charts that came to me had raspberry values, but none for the thornless
blackberries I grow. I soon found the raspberry values worked fine.
There's not much I can say if you're one of those people who truly prefer
sour grapes. Obviously, you can adopt the Brix method, but you would have
to use it in reverse.
> - much much more questions. I will save them for later.
Great. I hope I can help you understand a method that lets a consumer,
worried about quality, test their own food. It's of vital importance in
this day when we need to search out truly good food for our children.
I believe another of your messages mentioned Brix and the human body. I'll
go to that one to respond.
Hope I was helpful,
Rex Harrill
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