Today, I would like to discuss a point that may seem a bit technical. I will try to make it as simple as possible. If you make your own herbal products, it may explain what you have observed in your jars of tincture. If you are a professional maker of tinctures, you probably know a lot more than I do, so feel free to ignore this episode.
Some listeners may feel that I am a little picky with the details, but I like to understand stuff and look under the hood to see what happens. I hope you find this useful.
If you feel a bit lost in the details, at the end of the episode, I will summarize and simplify for you. Because we need to keep this practical.
So here we go. Tannins and alkaloids don’t play well together. These two are major families of medicinal constituents. We find them in many medicinal plants. Plants rich in tannins are oak bark, hazelnut leaves, Robert’s geranium, red vine leaves, plants of the Rosaceae family overall, etc. Alkaloids are a little less common, and you will find them in motherwort, fumitory, goldenseal, barberry, lobelia, corydalis, California poppy, red poppy. Plants of the Papaveraceae family are usually quite rich in alkaloids.
Binding explained
Now, here is the key point: when you combine those two families in a liquid, they can form insoluble complexes that will precipitate out of solution, reducing the potency of both of those compounds. Here’s how it works:
- Tannins have multiple hydroxyl (–OH) groups that act as weak acids. If you listened to my episode on tannins, you may remember that I used the octopus analogy, with many tentacles being the (–OH) groups of the tannins. So those many tentacles act as weak acids.
- Alkaloids, on the other hand, act as weak bases.
I don’t know if you remember middle school chemistry. Well, when I was in middle school in the 1980s, we learned that an acid plus a base in solution will lead to water and a salt. The salt precipitates out of solution.
Now, for tannins and alkaloids, this isn’t a simple acid-base reaction (like vinegar + baking soda, the reaction is quite clear). Instead, it’s a multi-point binding that creates large, insoluble clumps.
Let’s take an example. Say that you have restless legs due to poor blood circulation, which creates a problem of fragmented sleep. A simple mix could be hazelnut leaves with California poppy. The first one rich in tannins (tonic to the venous circulation), the other is rich in alkaloids (calms you down, acts as mild sedative). So what happens in your jar?
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- Well, if you prepare a tea, the reaction starts immediately, and those tannin-alkaloid complexes will start to form… But the high water content will keep some complexes suspended. If you let the tea sit for a while, say overnight, you might see some kind of fine sediment at the bottom. Those are the tannin-alkaloid complexes.
- Now, if you prepare a tincture with both plants in the same jar, or if you prepare them separately and then you mix those two, ethanol initially dissolves those complexes. But we keep our tinctures for very long periods of time, often years. Over time, there will be precipitation at the bottom of the jar.
What’s the big deal ?
Why does this matter for herbalists?
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- First of all, you have loss of potency: The precipitated complexes are no longer bioavailable when you ingest the liquid that is on top of the precipitate. It will be much weaker because most of the good stuff is resting at the bottom of the jar. So you can imagine for a big tincture jar (I don’t know what you do but I sometimes make big batches that I keep in 1 to 5 liters jars), it may take years to get to the bottom. Yes, you could shake well, but even if you do that, some precipitate will not be very absorbable by our body.
- As a consequence, you will have dosing inconsistency: The first dose from a tincture might be kind of weak, but the last dose (with all the precipitate) could be very concentrated—or completely inert depending on the nature of the precipitate.
Fixing this problem
So how do we avoid this problem?
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- Option 1: don’t mix high-tannin and high-alkaloid herbs in the same preparation. For example, we would avoid oak bark (rich in tannins) + barberry or coptis roots (rich in berberine, an alkaloid). Keep your tinctures separate. Mix at the last minute, in the glass, with a bit of water, to take your daily dose.
- Option 2: add glycerin to your tincture blend. Glycerin is a polar solvent that competes with tannins for alkaloid binding, slowing precipitation. Very often, the glycerin is added when you make the tincture of the plant rich in tannins, so then you can mix it with other tinctures without worrying too much about precipitation. This is a trick from Michael Moore’s Materia Medica, link to the free document on my website. For instance, to prepare oak bark or geranium tincture, Moore recommends 10% glycerine and therefore 90% alcohol to prepare your solvent (instead of 100% alcohol). Glycerin content usually varies between 10 and 20% max. By doing this, you “secure” (from a binding point of view) your tannin-rich tincture and mix it with whatever you want.
Is your solution acidic or alkaline?
Now, here is something people don’t know about: pH changes everything. The pH of your preparation dramatically affects binding.
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- In acidic conditions (with pH less than 6): I won’t explain the chemistry behind it, but the important point is that binding will be weaker. You might consider adding apple cider vinegar to your preparation and checking with pH paper strips. Adding vinegar is quite interesting when we prepare tinctures of alkaloid-rich plants, because it will also make the extraction better. This is explained in Richo Cech “Making Plant Medicine” book.
- In neutral or alkaline conditions (with pH greater than 7): binding will be stronger, leading to more precipitation. For instance, where I live, the water is very hard, so it is alkaline, and a tea with this water will precipitate more tannin-alkaloid complexes than one made with distilled water, for instance.
How basic is your alkaloid?
For the herbal geeks, let me get a little more technical and share some interesting information. For the non-geeks, put me on mute for a few seconds. So, another thing that people don’t know about: not all alkaloids are created equal. The basicity of the alkaloid determines how strongly it binds to tannins. And to see the level of basicity, you look at a number called pKa. The higher the pKa, the more basic your alkaloid is.
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- You have strongly basic alkaloids like berberine from Mahonia or Barberry (pKa ~11.5), quinine from Cinchona bark (pKa ~8.5) – they will precipitate readily with tannins.
- On the other hand, you have weakly basic alkaloids: caffeine (pKa ~0.6), theobromine (pKa ~0.2). These interact minimally with tannins.
- And somewhere in the middle, you will find a bunch of alkaloids that will somewhat precipitate with tannins.
Is this practical if you make home-based products? Not really. This is overkill.
Wrap-up and simplification
So let me summarize and simplify for you.
- For tea blends
- Don’t worry too much about this. The liquid won’t sit long enough to create a significant amount of precipitate. If you have tannin-rich plants and alkaloid-rich plants representing a large proportion of your blend, don’t let it sit overnight. Also, you may want to add a bit of lemon juice to make the water more acidic. But for most cases, don’t worry about it.
- For tinctures
- The simple way, again, is not to worry about all this. You make your tinctures the simple way with just the plant and alcohol; you mix your tinctures, you don’t worry about the precipitates. This is kind of OK with mildly active plants. It is not OK with strong plants, especially alkaloid-rich plants. There is a big difference between a precipitate of California poppy alkaloids and a precipitate of lobelia alkaloids. If you are a beginner, in any case, you shouldn’t use plants like lobelia. Stick to the simple, safe herbs.
- The intermediate way is to secure your preparations by using a trusted materia medica, like the one from Michael Moore or the book from Richo Cech. Use a bit of apple cider vinegar in your alkaloid-rich plant tinctures, and a bit of glycerin in your tannin-rich plant tinctures. That’s it. That’s your insurance against precipitation when you mix those with other plants. And when I say “a bit”, check the references for the exact percentage.
- The advanced way is to look at the main alkaloids of the plant, check their pKa to see if there is a risk. Frankly, not sure who does that. I shared the information for your own education, and because I like this kind of stuff. But it goes too far, and some plants have a whole bunch of alkaloids, making that pKa calculation complicated. Practically, we don’t need to go there.
OK friends, that’s it for this episode. Kind of geeky, I know, but still, I hope you found this useful.
Thanks for being here, and I will see you soon for the next episode of TheFrenchHerbal!
