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How to use Soxhlet's extractor?

Hello, I bought 30 grams of a six-year-old ginseng on the internet. I have a soxhlete and my questions are:

  1. How long to extract. The recommended 1 hour is slightly lower compared to a few weeks' lustration. Do I know that it's done?
  2. Is the extraction yield significantly higher than the yield?
  3. How many teaspoon drops or better. should I try my first experience with ginseng?


Hello and you, Mr. Jindrich!

Question 1. - How long to extract

The answer to this question will be somewhat longer with your kind remission. You can do it yourself - who asks you to know :-). In essence, Soxhlet is nothing more than a solvent recycling elution column. The extraction time on the column generally depends on four factors:

  1. the specific rate of diffusion of the extractant into the solvent
  2. granulometry of the extracted material
  3. the quality of the extractor construction
  4. temperature

Let's look at them point by point:

1. Specific rate of diffusion of the extractant into the solvent

Depending on the ratio of the affinity of the extracted substance to the extracted material / its affinity for the solvent and on the diffusion rate of the substance in the solvent of the soaked extracted particles, which in turn depends on the molecular weight of the extractant, the viscosity of the solvent and the internal pore size of the extracted particles. The property of the Soxlehet extractor is that it allows theoretical 100% extraction even if the ratio of affinities is very poor, ie the extracted material is much more likely to remain bound in the material than it is dissolved in the solvent - only in this case it takes longer. In the case of ginseng, fortunately, you do not have to worry about these problems - the active substances in gins are not tightly bound, their molecular weight is low (max 100 Da), and those less polar dissolve at least a bit in that pure water, not to mention mixtures water and alcohol.

2. Granulometry of extracted material

The finer grind, the faster the diffusion out of the particles, but the greater the flow resistance of the column. The particle shape also plays its part. I'm not a specialist in laboratory methods, but from cell biology I remember a simple rule that at body temperature, diffusion at micrometer distances occurs in fractions of a second, tens of millimeters in seconds, and hundreds of microns in minutes. In our specific case of ginseng root, there are three possibilities - to sow the slices there as they are, grind them roughly (perhaps cut them off) or grind them to a fine powder (which is usually done on a coffee grinder with rotating knives, as I have already written in another answer on our site ). In this particular case, it would probably be technically optimal to grind as gently as possible with regard to the flow of the cartridge, but if you do not do it on an industrial scale, you do not have to do that - it is almost as good to use the slices as they are.

3. Quality of extractor design

For the ideal column and the ideal solvent, the elution time is asymptotically approaching the solvent flow rate by a column (= cartridge) that I would estimate for a regular larger Soxhleth in order of minutes. However, we use Soxhlet just to overcome difficult extractions, so we expect that we will need dozens of flow rates. The rate of flow through the cartridge is limited by both the distillation power of Soxhleth and the flow rate of the cartridge itself (limiting the lesser of the two values). Another problem is the regularity of the flow - if, for example, the distillate falls in the middle of the cartridge, the core of the column is rummaged quickly while the edges are lagging behind. These parameters depend on the construction of your extractor, so you have no chance to influence them.

4. Temperature

Special mention is made of the temperature. The working temperature of the normal Soxhlete is right at the boiling point of the solvent used at the given pressure and can only be controlled by changing the pressure. At higher temperatures, faster diffusion and better extraction, but lower temperatures are required for sensitive substances. For ginseng, you do not have to deal with this again - Panaxosides can easily survive long cooking in the water and the boiling point of the alcohol mixture is even lower.

To summarize:

Ginseng , and especially red ginseng , is so easy to extract for extraction that we can handle it even without inferior quality extractor without calculations. By carefully reading the extraction page , you may notice that I do not say to extract an "hour" but "at least an hour". I expect that the elution column will trip several times the effective length of the extraction cartridge per hour in the inferior extractor, which should be enough for red ginseng. I do not want extraction time longer than an hour to prescribe. Panaxosides are very stable, but some of them are slowly decomposing by removing sugar and malonyl residues. It is unclear whether this fission is good or bad. In Asian recipes, long ginseng cooking is strongly recommended, but red ginseng has already had a long stew during its production. That is why I do not want to prescribe another long cooking. For multi-weekly leaching, this takes place at a lower temperature of 80 ° C. We know that, around room temperatures, the rate of normal reactions increases roughly twice as the temperature increases by every ten K. At 20 ° C it is about 256 times slower than at 100 ° C - therefore, instead of hours, we have to lie weeks at room temperature.

How do you know it's done

The color of red ginseng is lost during leaching. Completely sliced slices increase, lose taste and aroma and get a gray-white color that does not change with other leaching. They are called ginseng cakes and usually still contain immunostimulatory polysaccharides.

Question 2 - If extraction is better than leaching

Almost or no, but better, is to use the alcohol mixture instead of pure water - it is easier to dissolve non-polar substances and panaxosides that have lost their carcass as a result of the heating of some sugars. And if you are using alcohol and do not want to lie for weeks, you have to boil at the boiling point, which you can not do in a mug on the plate, because you will soon evaporate not only the majority of alcohol but you will also find most of the volatile fragrance substances delivering ginseng its typical aroma . For this reason, you need to brew alcohol in a confined space, that is, in an extractor in which the leaking vapors of the solvent are condensed and recycled.

Question 3 - How many tinkers to get to ginseng

I personally recommend to a regular user a daily dose of 5-6g of red ginseng. At this dose, we can clearly distinguish the effects of ginseng, which can be subjectively assessed by the user: mental activation , improvement in erection , or reduction of pain , inflammation and autoimmune conditions . More specifically, the user will clearly know whether or not ginseng occupies it and how, as with any other medicine, or ginseng does not always work. For greater effect and greater certainty, considerably higher doses can be used - ginseng as a model adaptogen does not even harm the physiological state of the unbalanced organism.

As far as the liquid extract is concerned, you must know how much tincture you have prepared (how many grams of drug do you have in 100ml). For example, if you have 25g dry ginseng in a 100ml extract, you need to take 20ml of tincture to get the equivalent of 5g ginseng in a dry state. Alcohol in milliliter doses is said to be beneficial. If you want to be absolutely sure you are only familiar with ginseng, you can of course use water leach. The required dose of ginseng depends on your metabolism and weight. Follow your feelings, you will not be ginseng.


| 31.1.2009

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