We're going to make the
agarose plugs to measure pH and conductivity of a
surface of a work of art. We're going to use Benchmark
agarose electrophoretic grades. So it's high purity,
low conductivity. We're going to
make a 4% solution. So we take 100 mills of water,
plus or minus the amount isn't critical. Place it into a
plastic container because when we cook
in the microwave we will not want to
handle a glass container because it gets very hot. We'll measure out 4
grams of the agarose, and mix that into the
deionized or distilled water. It's best to cook
it in a microwave. Current thought is that
it's best to cook it twice. So it goes into the microwave. And first we do 30 seconds-- [BEEPING] --on high. [BEEPING] [MICROWAVE SOUND] [BEEPING] [OPENING MICROWAVE] We take it out. It's just starting to get warm. Give it a quick stir to make
sure everything's uniform and well dispersed. And then thereafter we do
it in 10 second increments until it reaches boiling point. [CLOSING MICROWAVE] [BEEPING] [MICROWAVE SOUND] You have to be very careful
because the agarose can superheat and bump. So you can boil
over very quickly and you don't want to get
boiling agarose on your hand. Starting to get warm now
and starting to thicken up. So we'll do another 10 seconds. [BEEPING] [MICROWAVE SOUND] [BEEPING] [OPENING MICROWAVE] It's getting quite warm,
thickening very nicely. When it boils it tends to
foam up like a souffle. It can come up to that
height, so you always want to use a plastic
container that is well above the height of
the liquid that you're heating. [CLOSING MICROWAVE] Another 10 seconds. [BEEPING] [MICROWAVE SOUND] [BEEPING] [OPENING MICROWAVE] And you can see it has foamed
up and is now coming back down. So very carefully not
touching where the liquid is, we remove it, stir. I'm going to give it one
more five second pulse. [CLOSING MICROWAVE] [BEEPING] [MICROWAVE SOUND] [BEEPING] Now, we'll let
this cool and gel, and then we'll melt it again
using the same process. [CLOSING MICROWAVE] [BEEPING] So we've let it cool and
we're heating it up again, melting it again. It seems the agarose
performs better if it's cooked twice, both
for treatment and for better clarity of the gel. So here we have it melted again. You have a choice at
this point of adding a preservative or not. Without the preservative it will
be a wonderful medium for mold to grow. With the preservative you have
to wash the preservative out before using it for measurement. So we're going to
add preservative, going to add four drops
of Germaben II, and stir. And then we'll pour it
into the macaroon molds. I prefer to use thicker
plugs of agarose, and some people use very thin. We let the agarose cool
in the macaroon mat. So now that the
agarose is cooled, we can just pop
it out of the mold and put it into a plastic bag. We don't want to touch the
agarose with our fingers because there is
salts on the fingers. This is the fun part. And then just use tweezers
to pick them up and put them in the bag. So they're in the bag. Because we've
added the Germaben, they won't grow mold
for quite a while. You want to keep as little
air in the bag as possible because they will lose
moisture slowly and dry out.
