The headline number from American Kava Association Technical White Paper No. 2 is that 85.1% of the kavalactone in the root reached the cup. That figure is not a property of kava — it is a property of a procedure: a short warm-water extraction (SWWE) of fresh, frozen root, macerated 30 seconds at high speed and hand-kneaded through a 150 µm nylon bag over three cycles. This article sets out that procedure step by step, shows what the preparation actually looks like, and explains why between 78.7% and 97.2% of the kavalactone delivered to the cup rides on fine solids rather than dissolving in the water.
Thirty seconds, three cycles, one 150 µm bag: the short warm-water extraction behind the numbers
Technical White Paper No. 2 · Methods
Thirty seconds, three cycles, one 150 µm bag: how fresh-frozen kava actually becomes a beverage
The headline number from White Paper No. 2 is that 85.1% of the kavalactone in the root reached the cup. That number is not a property of kava. It is a property of a procedure — a short warm-water extraction of fresh, frozen root, macerated at high speed and strained through a 150 µm nylon bag over three cycles. This is that procedure, written out so it can be repeated.
- Fresh frozen root
- 150 micron nylon mesh
- 3 extraction cycles
- 85.1% transfer
The head that forms on a fresh-root preparation seconds after maceration. The warm yellow-gold cast in the head is the most visible sign that this is not clear kava water.
Starting material
Why the study started with frozen fresh root, not powder
Almost everything the kava trade believes about potency is inherited from analyses of dried root: a laboratory grinds a sample, extracts it with an organic solvent, and reports a percentage. Nobody drinks solvent extract. People drink a warm-water suspension made by kneading root in a straining bag — and the two are not the same measurement.
White Paper No. 2 closes that gap for three American-grown cultivars. Kali-ISA, Kali-Hiwa and Kali-Rogu were grown in the American Kava Association Research Greenhouse in Sacramento, California, and harvested at three years of age. Roots and rhizomes were homogenized on a Robot Coupe CL60 and flash-frozen at −20 °C. Each cultivar contributed one characterized lot, from which three independent preparation runs were made; a separate single run was made from Kali-Hiwa lateral roots.
Freezing the homogenate is what makes the accounting possible. A fresh lot can be homogenized once, split into identical 454 g portions, and held indefinitely at −20 °C, so every run in a series starts from chemically identical material. That is why the study could report process replicates at all — and it is the same reason a fresh-frozen product behaves so consistently on a kava bar line.
What frozen fresh root is, in one line
Fresh root, cleaned and homogenized within hours of harvest and frozen wet — never dried, never milled, never reconstituted. It is the format the beverage was historically made from, and the format this study measured.
- 454 gFrozen homogenate per run
Thawed at 23 °C for roughly ten hours before preparation.
Thirty seconds on high
One maceration cycle of thawed fresh-frozen homogenate in a Vitamix 5200. The slurry goes opaque almost immediately — that opacity is fine root solid entering suspension, and it is where most of the kavalactone will travel.
The method
The short warm-water extraction (SWWE), step by step
Reproduced from Section 2.3 of the white paper. Every parameter below was fixed for the whole study; none of them was tested against an alternative, and no claim of optimality is made for any of them.
Thaw
454 g of frozen homogenate thawed at 23 °C for approximately ten hours.
Combine
Thawed material combined with 1250 mL of filtered tap water at 38 °C, adjusted to pH 8.0.
Macerate
Vitamix 5200 (1800 W), high speed, 30 seconds.
Strain and knead
Slurry transferred to a 150 µm nylon straining bag and kneaded by hand for approximately 40 seconds — until flow slowed to roughly one drop per second.
Repeat
Three cycles total, with fresh water each time: 3750 mL added in all.
Weigh the marc
The spent root left in the bag was dried in an Avantco 1000 W dehydrator for 48 hours at 38 °C to ≤3.0% moisture, verified on a U.S. Solid USS-HMA21 moisture analyzer, then weighed and assayed alongside the beverage and the raw material.
Fixed parameters
Every value fixed across all runs in the study.
| Parameter | Value |
|---|---|
| Starting material | 454 g frozen fresh-root homogenate |
| Thaw | 23 °C, ~10 h |
| Water temperature | 38 °C |
| Water pH | 8.0 |
| Water added | 1250 mL × 3 cycles = 3750 mL |
| Maceration | Vitamix 5200 (1800 W), 30 s on high |
| Mesh aperture | 150 µm nylon |
| Kneading | ~40 s per cycle, to ~1 drop/second |
| Cycles | 3 |
| Final beverage volume | 4000 mL |
| Serving definition | 125 mL |
Measured final beverage volume (4000 mL) exceeds the 3750 mL of added water because the thawed plant material releases its own moisture during maceration; that water enters the beverage. This is expected with fresh-frozen material and does not occur to the same degree with dried powder.
One condition, not a comparison
Warm, slightly alkaline water was used because it is common practice among American preparers — not because the study tested it against alternatives. Temperature, pH, mesh aperture, cycle count and maceration time were all fixed. No comparison of conditions was performed and none is claimed.
What you can see
The foam on top, and the yellow in it
Stop the blender and a thick head builds within seconds. It is not froth on water. It is an emulsion of fine root solids and released plant oils — and it carries a warm, faintly yellow-gold cast.
Fresh-frozen homogenate immediately after maceration. The pale, dense head is an emulsion of sub-150 µm root solids and released oils; the warm yellow-gold cast is characteristic of the kavalactone-bearing fraction.
The colour is worth a sentence of chemistry. Kavalactones are not all colourless: the two most conjugated members of the group, yangonin and desmethoxyyangonin, absorb far enough into the visible to read yellow in bulk — which is exactly why the laboratory quantifies those two at 355 nm while methysticin, dihydromethysticin, kavain and dihydrokavain are read at 240 nm. When the head on a fresh preparation reads yellow-gold rather than grey, that is the visible end of the same chemistry the HPLC is measuring.
Stated precisely
The foam layer was not separately assayed in White Paper No. 2. What the study did measure is where the kavalactone in the finished beverage sits — and the answer is overwhelmingly on the solids, which is the same material the emulsion is built from.
- 78.7–97.2%Of delivered kavalactone was particle-associated
Depending on lot. The corresponding non-particulate residuals were 21.3%, 14.7% and 2.8%. A one-way ANOVA across lots gave F(2,6) = 85.3, p < 0.0001, η² = 0.97 — by a wide margin the strongest effect in the dataset.
The drink is therefore a suspension in which the great majority of the active material is carried on solids fine enough to pass a 150 µm mesh, not dissolved in the water. That resolves the long-standing contradiction between kava's low aqueous solubility and its obvious potency as a beverage: potency does not depend on dissolution.
Two consequences at the bar
Grind and mesh are the strength controls. Anything that changes how much solid crosses the bag changes potency roughly in proportion. Standardizing the bag and the grind standardizes most of the product variability; standardizing water temperature alone does not.
A settled beverage is not a uniform beverage. Particulate separates on standing, so a serving poured from the top of an unstirred vessel does not carry the dose of one poured from the bottom. Agitation before pouring is a dose-control step, not presentation.
The partition between the particle-associated fraction and the non-particulate residual is an exploratory estimate. The non-particulate fraction is an operational residual computed by difference, not a direct solubility measurement, and it absorbs any error in the terms it is derived from.
The exact strainer bag used in the study
Because the mesh is the strength control, the bag is not an accessory — it is an experimental parameter. Every run in White Paper No. 2 was strained through a 150 µm nylon bag, and this is the bag we use and sell. If you want your preparation to sit anywhere near the numbers in this paper, start by matching the mesh.
Kava Strainer Bag
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What the method delivered
85.1% transfer, and 188–452 mg in a 125 mL cup
Warm-water extraction recovered most of the available kavalactone. Overall transfer across the study was 85.1%. Kali-ISA was the most complete and the most consistent, Kali-Rogu close behind, and Kali-Hiwa both lower and far more variable.
Table 2
Extraction efficiency, dry-matter pass-through and per-serving potency by lot. Triplicate values are mean ± SD of three process replicates from a single characterized lot.
| Lot | Extraction efficiency (%) | Dry-matter pass-through (%) | Total KL per 125 mL (mg) |
|---|---|---|---|
| Kali-ISA (n = 3) | 90.4 ± 1.2 | 71.1 ± 1.4 | 447 ± 5.8 |
| Kali-Hiwa (n = 3) | 80.7 ± 7.3 | 78.3 ± 5.1 | 205 ± 19 |
| Kali-Hiwa laterals (n = 1) | 78.7 | 74.4 | 334 |
| Kali-Rogu (n = 3) | 84.1 ± 0.5 | 71.7 ± 1.3 | 228 ± 1.2 |
| Overall | 85.1 | — | 188–452 (range) |
These are process replicates, not biological replicates. Three runs from one lot measure the reproducibility of the preparation and the analysis — not variation between plants. Every cultivar difference here is a difference between three specific lots.
- 9.5–19.3%Of starting kavalactone stayed in the marc
Even after three cycles there is real material left in the bag. Whether recovering it is worth the dilution it costs is a business decision — but it should be a deliberate one.
Efficiency was not uniform across the six kavalactones. In every cultivar dihydrokavain transferred most completely and yangonin least — 78.0% versus 88.4% in Kali-Rogu, 76.4% versus 86.5% in Kali-Hiwa, and a narrower 88.5% to 92.3% in Kali-ISA. That ordering tracks published aqueous solubility, which runs from 8.1 mg/100 mL for dihydrokavain down to 0.3 mg/100 mL for yangonin at 21 °C — but the effect is modest against a large particle-transported background.
Set against the small published literature that measured finished beverages rather than root, these servings are strong. Normalized to a common 125 mL, the traditional Hawaiian preparations of Brown and colleagues give approximately 89 mg, the traditional-method infusions of Jhoo and colleagues approximately 115–173 mg, and Micronesian sakau approximately 174–250 mg. The present range of 188–452 mg sits at or above the top of that span. The comparison is indicative only: preparation methods, root-to-water ratios and analytical methods differ across all four studies.
Do not read 85% as a property of kava
Historic Fijian work by Duve and Prasad reported recoveries in the region of 22–29% under some conditions and 81–83% under others, and lower figures still circulate in the trade as rules of thumb. The 80.7–90.4% found here reflects a specific combination — frozen fresh homogenate, high-speed maceration, warm water and three sequential cycles — and should not be read as a general property of the plant.
Beyond the three American lots
The same protocol, run on Hawaiian and Fijian fresh-frozen material
White Paper No. 2 reports three American-grown cultivars. The same short warm-water extraction has since been run in-house on fresh-frozen material from other origins — Hawaiian, Premium Fresh Frozen Fijian and Superior Fresh Frozen Fijian — so that the protocol can be compared across sources rather than across preparation styles.
Scope note
Those additional Hawaiian and Fijian studies are separate in-house work. They are not part of White Paper No. 2, have not been peer reviewed, and no figures from them are reported on this page. Only the three American-grown lots — Kali-ISA, Kali-Hiwa and Kali-Rogu — are covered by the published data above.
The reason for running them at all is the one the paper is careful about: nothing in a three-lot study can tell you whether a difference belongs to a cultivar, an origin or a growing season. Holding the method rigidly constant and changing only the material is the only way to start separating those. Fresh-frozen root makes that practical, because a lot can be homogenized once and split into identical portions before a single run is made.
The kavas below are the same fresh-frozen formats those preparations were made from. All of them go through the same cleaning and processing standard, and all of them are handled and shipped frozen.
Fresh Frozen Kava
Kava as close to the freshly harvested root as we can deliver it — processed from fresh root and frozen rather than dried. Expedited frozen shipping is included in the price, and fresh frozen ships separately from the rest of your order.
Sources and disclosures
Credits
This article reproduces the methods and results of American Kava Association Technical White Paper No. 2. Where it goes beyond that paper — the additional Hawaiian and Fijian preparations, and the description of the foam layer — it says so on the page.
Suggested citation. Blythe, T.; Bowman, J.; Masifilo, M. Where the Kavalactones Go: A Mass Balance of the American Kava Beverage. American Kava Association Technical White Paper No. 2, version 1.0; American Kava Association: Las Vegas, NV, USA, August 2026.
Analytical work. Flora Research Laboratories, LLC, Grants Pass, Oregon, USA (job J25-0930-H, 9 October 2025). Identity by HPTLC against an authenticated Piper methysticum reference. Quantification by HPLC-UV on an Agilent 1200 RRLC with a Poroshell 120 SB-C18 column, eight-point calibration 5–250 µg/mL, R² ≥ 0.999; 240 nm for methysticin, dihydromethysticin, kavain and dihydrokavain, 355 nm for yangonin and desmethoxyyangonin. Method adapted from Liu, Y.; Lund, J.A.; Murch, S.J.; Brown, P.N. (2018).
Comparative beverage literature. Brown, A.C. et al., Traditional kava beverage consumption and liver function tests; Jhoo, J.-W. et al., Assessment of kavalactones in kava beverage products and aqueous infusions, J. Food Sci.; Balick, M.J.; Lee, R., Traditional use of sakau (kava) in Pohnpei, Altern. Ther. Health Med. 2002, 8, 96–98; Duve, R.N.; Prasad, J., Efficacy of extraction of constituents in the preparation of yaqona beverage, Part 2, Fiji Agric. J.; Lebot, V.; Michalet, S.; Legendre, L., aqueous solubility values.
Cultivation. Three-year plants grown at the AKA Research Greenhouse, Sacramento, California.
Disclosures. The authors are commercially engaged in the kava trade. Tyler Blythe is affiliated with Root of Happiness, which supplied material and sells the products featured on this page; Matthew Masifilo is affiliated with Kavafied; Jeffrey Bowman is affiliated with Nakava. No comparison against any competing preparation method or apparatus was performed, and no claim of superiority over manual preparation or over any commercial device is made.
Not medical advice. Nothing here is a health claim or a recommendation of dose.