What's actually in a shell of kava? For a new study in The Journal of American Kava, five Root of Happiness kavatenders each hand-mixed kava to the same written recipe, and an accredited laboratory measured all six batches. Below is a short look at what the paper found, and at the part our kava, our staff and our Rancho Cordova bar played in it.
What's in the Shell? Root of Happiness Kava Research
The Journal of American Kava · Article 023
What's in a 12-ounce shell? Five kavatenders, one recipe, six lab-tested batches
How much kava is actually in a hand-mixed shell? For a new study in The Journal of American Kava, five Root of Happiness kavatenders with 2 to 12 years behind the bowl each prepared kava by hand to the same written recipe, and an accredited laboratory measured every batch. A 12 fl oz shell delivered a mean of 337 to 378 mg of kavalactones, depending on the lot.
- 6 lab-tested batches
- 5 kavatenders
- One written recipe
- 12 fl oz shell
The study in brief
One recipe, measured six times
Each batch combined 226.8 g (half a pound) of ground kava with 5.68 L of water at 38 °C, worked by hand in two two-minute washes through a 150 µm strainer bag, the same way our kavatenders mix at the bar. Three batches came from each of two Root of Happiness lots, and an unfiltered sample of every batch went to the lab for kavalactone and flavokavain analysis.
- 337 mgkavalactones per shell, House Vanuatu lot (mean)
Batch-to-batch variation of 8.6% across three kavatenders.
- 378 mgkavalactones per shell, House Fijian lot (mean)
Batch-to-batch variation of 6.7% across three kavatenders.
- r = −0.95spent root left in the bag vs. strength of the shell
The batches that left the least dry root behind in the strainer bag were the strongest.
- 15.6–15.812-ounce shells per six-quart batch
The spent root holds back some water, so a batch pours a little under sixteen shells.
The takeaway for anyone who mixes kava: a written recipe produces consistent shells, and how thoroughly the root is worked through the bag looks like the variable worth watching. The authors call the study exploratory, since most kavatenders made one batch each, and follow-up trials with repeated batches per preparer are already underway.
Our part
Proud to put our kava and our kavatenders behind the research
Root of Happiness is excited to contribute its kava and its expert staff to the furtherance of kava research. Questions like “what's actually in the shell?” are best answered by the people who mix kava every day, and we were glad to open our bar, our stock and our team to this study.
Our kava
Both lots came from Root of Happiness. House Fijian is a lot we serve. House Vanuatu was a lot our own quality standards had turned away from the bars, so we donated it to the study. It was never sold or served.
Our kavatenders
Five Root of Happiness kavatenders, with 2 to 12 years of daily preparation experience, mixed the batches using their everyday technique. Our own Kyle Garrett is a co-author of the paper.
Our bar
Every batch was prepared on 19 September 2026 at Root of Happiness Rancho Cordova, at the same counter where we mix for guests.
Kava mixed by hand and served the traditional way at Root of Happiness.
Make it at home
The study recipe, step by step
This is the written recipe all five kavatenders followed. Everything you need to make it is below.
Weigh half a pound of kava
226.8 g of ground kava, one 1/2 lb bag.
Split six quarts of warm water
5.68 L of water at about 100 °F (38 °C), divided into two washes of three quarts each.
Knead and squeeze for two minutes per wash
Load the kava into a 150 µm strainer bag, immerse it in the first wash, then knead and squeeze for two minutes and press until it stops draining. Repeat with the same kava in the second wash.
Combine, stir and pour
Combine both washes and stir. A batch pours just under sixteen 12-ounce shells. Work the root thoroughly: in the study, the batches that left the least behind in the bag were the strongest.
Premium Vanuatu Kava
Our house kava, and the Vanuatu our kavatenders mix at the bar every day. A blend of Santo Island Borogu and Melo Melo peeled chips, ground for hand preparation. One 1/2 lb bag is exactly one batch of the study recipe.
Vanuatu Kava Powder - Premium 1/2lb
Regular price
$ 33.00
Shipping calculated at checkout.
Superior Fijian Kava
Pure waka from Taveuni, Fiji's Garden Island: whole long waka lateral roots from Matakaro Balavu, Qila Leka and Doko Bana Vula, with no peelings or crowns. A 462 chemotype and at least 8.0% total kavalactones.
Fijian Kava Powder - Superior 1/2lb
Regular price
$ 37.50
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The strainer bag from the study
Every batch in the paper was squeezed through a Root of Happiness 150 µm nylon strainer bag. It's food-safe, BPA free and washable, and fine enough to hold back the fibre while letting the right particles through.
Kava Strainer Bag
Regular price
$ 6.99
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Credits and citation
Sources and disclosures
Citation. Blythe, T.; Lowin, T.; Garrett, K. Kavalactone delivery and between-batch variability across five preparers in traditionally hand-prepared kava: An exploratory study of the 12-ounce shell. J. Am. Kava 2026, 2, 023. journalofamericankava.org/articles/hand-prepared-kava-shell
Analytical work. Kavalactones and flavokavains A, B and C quantified by LC-DAD at Cambium Analytica, Traverse City, Michigan, an ISO/IEC 17025:2017-accredited laboratory.
Scope. Per-shell values describe these two lots under this recipe. They are reference measurements, not a serving recommendation.
Disclosures. Tyler Blythe and Travis Lowin hold ownership interests in Root of Happiness, and Kyle Garrett is employed by Root of Happiness. Tyler Blythe founded the American Kava Association, which publishes The Journal of American Kava. All analytical data were generated by an independent laboratory.