Hi, this is Thomas Easley, planning director of the Eclectic School of Herbal Medicine, and the co-author of the Modern Herbal
Dispensatory, and today I'm with Mountain Rose Herbs, and we're going to demo how to
do an herbal percolation. Percolation is one method to make herbal tinctures.
The other most common method is maceration, where you stick things in a
jar, and cover them in alcohol, and let them soak. They normally take three to
six weeks of a soaking with daily shaking to get all the
constituents that are in the plant into your solvent, into your alcohol water
mixture.
Percolations are convenient because they're normally done in like 24
to 48 hours. They take a little bit more work, but they're not quite as
complicated as a lot of people think, so let's dive right into it. For a
percolation, you're gonna need a percolation cone, and you can pay a
scientific glassblower a lot of money to make one for you, or you can use a wine
bottle that you've cut the base off of.
A lot of people do the string and fire
method to get the bottom off, and there are glass cutters. What I found is that a
wet tile saw works really well to make a smooth cut that there's no chance of,
you know, getting an edge that's going to cut you. The wet tile saw you could buy
new, but probably you have a neighbor that's remodeled their house and installed
tile flooring. Borrow one from a neighbor, cut the bottom off … I like the
one and a half liter wine bottles because you can get your hand in there,
so they're easier to clean.
Once you've cut the base off, the other side is
going to be a way to control your flow rate. And, a lot of people use, instead
of wine bottles, they use water bottles with an adjustable lid and they control
the flow rate too by tweaking that lid a little bit tighter a little
bit looser. One of my friends, Darrell Patton from Alabama, figured out that you
could use a needle valve that you can purchase at most hardware stores, and I
played around with a lot of different stoppers and found a food-grade silicone
stopper that works well. So we're going to use this to control our flow rate.
Then you need a container to catch your tincture in, and if you need some way
to hold that, you can just take your percolation cone and set it right into a
jar, but then you have to move it up every time you need to adjust your flow
rate with your valve. And so what I recommend is getting a lab stand. You can
pick one up for about 30 bucks, and it's like getting an extra set of hands,
which is really helpful when you're preparing herbs.
So what we're going to
do today is make a percolation of Echinacea angustifolia.
All percolations are done with dried, powdered herbs (you can't percolate fresh
herbs). So, we're going to get our powder… (See? Extra set of hands!)
We're gonna take our herb powder and we're gonna weigh it out because, unlike
the folk method, when you are doing percolations, you're going to go with a
weight-to-volume ratio. So a standard weight-to-volume ratio is 1 to 5. That
means 1 gram of plant material that's dried and powdered (and preferably sieved
through like a number 60 screen), 1 gram of that per 5 milliliters of whatever
solvent that you're using. In this case, we're going to do a mixture of water and
alcohol at a 50% alcohol volume.
So in a one and a half liter wine bottle, magnum
wine bottle size, you can get about a hundred grams
herbs with enough space left for your menstruum. So we're going to weigh out a
hundred grams. Good to go. So, if we were to dump this dried herb powder into our percolation cone, once our water-alcohol combination hit it, it would swell up and would not let fluid flow through, so we have to pre-moisten our powder, and we do
that with the same solvent that we're using (in this case, 50%
ethanol.) The technical way to do it is to take your powder put it into a
volumetric flask, compress it see how much it displaces, and then you're going
to pre-moistened about 65% of your displaced volume.
We're just going to
eyeball it, because we're going for a specific consistency of wet sand. So, we take our menstruum, and add a little bit in, and give it a stir. And we're just trying to rehydrate our
powder, so that the cell walls expand to their maximum size and it doesn't swell once we add our menstruum in. So this process of adding a little bit
of your menstruum and then working it in and making sure that it doesn't swell, or
that it is fully-swelled but it's not still drying,
this takes experience. I recommend the first few times you make percolations, use the cheapest powdered herb you can find, so that if you mess it up, you
know, you haven't just tried to percolate five hundred bucks worth of American
ginseng.
Use of something maybe that you have leftover or that's
inexpensive, and play around with this process. So we're getting to a pretty
good consistency. What you'll find when you're pre-moistening your plant
material is that things will look really good, and then you'll come back like
twenty minutes later, and it's sucked in more water, so you have to keep adding
and tweaking for the first hour or so to make sure that it's the right
consistency. And once you get things looking the right consistency, you
want to put something over the top to prevent your menstruum from
evaporating, and then let it sit and just soak in and hydrate for at least two hours
(a lot of people say 12 to 24 hours) but normally, you know, two or three hours and we're good.
So this will need to sit aside and make sure that it's absorbed
all of the moisture. I have already pre-moistened another
batch, and this is the consistency that we're looking for: it is wet sand,
like, it clumps in your fingers, but falls apart pretty easily once you drop it.
So we have our Echinacea that has been pre-moistened, it's at the right
consistency, now we're going to pack our cone. A lot of times when you pack and do percolations, or see classes on percolations, they'll put a coffee
filter in the bottom to hold the plant material up. I did it that way
for years, and then maybe a year ago somebody said, "why don't you just use
cotton balls instead?".
So you can get these unbleached organic cotton balls
and just shove them in the neck of your percolation column, and that will hold
your plant material off of the bottom and allow some space for fluid to fill.
And we're going to put our valve in and you want to be sure with these silicon
valves (because they're pretty slick), that you really press it in there. And then
we're gonna open our valve up because, as fluid moves through, it's going to
displace the air, and if we keep our valve closed, those air bubbles will come
up and disrupt our packing of our pre-moistened herb. So we're gonna open
that up until everything runs through. Then we're just going to tighten this down
and start adding our plant material. This is done in thirds. You're going to dump about a third of your plant material straight into your percolation
cone.
And once you get about a third of your
plant material in there, you need to slightly compress it. So we're going to
tamp it down and what we're doing here is just making sure that the consistency
of the powder is even, because we want an even movement of our menstruum through
our plant material. If you over pack, if you tamp down too hard, then your fluid
won't be able to make its way through. If you tamp down too loose, then your
powder, once you add your menstruum, will kind of float, which is not great.
So
it takes practice; I've been doing this for years, and I still mess these up
every now and then (I pack them too tight, or I don't pack them tight enough),
but once you get hang of it, it's pretty easy to stay consistent. So we
have that packed in now, we've got a hundred grams, and we're gonna do a 1-to-5 extract, so we're gonna add 500 milliliters of our solvent. So if we
just add it right now, it's going to disrupt the packing, and all of the plant
material will start to float around and you won't get an even movement of your
solvent through your plant material, so we're going to take an unbleached coffee
filter and put it in, and just kind of press it in place so that when we add our solvent, our powder won't float to the top. Now what you're looking for, is an even movement of your menstruum through your plant material, so keep an eye on your moisture level as it moves down and, it should be moving at about the same speed all the way around.
If it's not, then I have kind of packed it equally. That
looks good, you can see the menstruum flowing through evenly through the plant
material, and that's about two-thirds through now, remember that our valve is open. Now at
this point if your valve is closed, all of the air that the fluid is pushing
will bubble back up, and you'll get little rivers through your powder, and
you won't get an even movement of your solvent.
So keep the valve open
until you start getting your solvent dripping through your menstruum, dripping
through the bottom, we're down to about here. One of the benefits of percolation
is that you're moving unsaturated solvent here at the top through the
plant material, and extracting the stuff that's inside of plants works via a
constituent or a concentration gradient, so your menstruum will only pull out
half of what is inside the cell walls of the plant, but because our menstruum is
unsaturated, as it moves through, it's going to pull a little bit more than if
we did a standard maceration.
Now there are no studies on this that I'm
familiar with, but the general consensus is that percolations (which can only
be done with dried herbs, so there are some drawbacks) but percolations are
somewhere between like ten and thirty percent more potent than standard
macerations. I definitely have plants that I prefer doing standard
macerations on, but the majority of the dried herbs that we turn into tinctures,
I like this process of percolation. So we moved all the way through the
plant material now our cotton balls (our filters) are
slowly filling with our liquid. There's the first one, so we're going to get
ready, as it filters through, to close our valve once all of that air has been
displaced.
And of course if a few drops go through it's no big deal, but the idea is to … there we go, our liquid's at the bottom, the air is displaced, it starts to drip, and we just
close our needle valve. Now, at this point at this point, we pause and we let this menstruum sit with our plant material for about 12 hours, and that process is called digestion. And once our plant material has been
digested by our menstruum, that means that the solvent (the menstruum that is in
contact with the plant material) has had enough time to pull the constituents
from inside the cell wall out into solution. Once that 12 hours has passed,
we're just going to start our percolation dripping. So let's just
pretend the 12 hours has passed. We're just going to adjust our valve so that
we get one drip every three to five seconds. So a slow, steady drip of about one
droplet every three to five seconds, and this is, you know, set overnight and
digested. This is going to take a couple of hours to move the continual
unsaturated solvent through the plant material, and then, in a couple of hours,
your tincture is ready.
So percolation: fairly easy to do, you do need to do a
little bit of weighing and measuring to make sure that you have a good weight-to-
volume ratio (one-to-five is the most commonly used one …you can do one-to-one fluid extracts with a few extra steps), and once you've weighed and measured
everything, pack it in thirds, remember to keep your valve open until
it starts to drip, close it off, let it sit 12 hours, and then open it back up so
you get one drip every three to five seconds.
You'll have a finished
tincture ready to go within about 24 hours of starting this whole process, and
that's how you make percolation-based tinctures..