Micro-Batch Home Tea Making as a 10-Step Process

1. Wash hands and wash or otherwise fungus-proof a pair of pruning scissors or large surgical steel scissors.

2. Trim tips (from 3 to 6 leaves back) of branches of the tea bush. I like to keep the tea trees in a hedge form, about one meter high and compact enough so that I can trim the top back branches comfortably while standing in front of the tree/bush.

3. Take trimmings to kitchen table and wash hands again. Pluck leaves from stems. I like to leave the base of larger leaves attached to the stem since such leaves have a woody lower vein. On the other hand, the tips of the shoots are tender enough to be included with the leaves.

4. Place in the dehydrator for at least 1/2 hour at the lowest setting. This helps the leaves wilt. Note that in our rainforest humidity, tea leaves will take a long time to wilt in the sun, but in a drier climate you may not need the dehydrator at this stage. Just leaving the leaves out in the hot sun for an hour would likely be sufficient.

5. Wash hands again. Take out the leaves and crush, then roll lengthwise until they appear somewhat muddied and the smaller leaves start to brown. This takes a quarter hour for a small batch and proportionately longer for bigger batches. Curling the leaves into a roll lengthwise individually preserves the leaf size, but takes longer to evenly bruise the leaves than does stacking the leaves and twisting and wringing the stack like a a wet cloth. An even faster way to process larger batches by hand is to stack them about 10 cm high inside a thick ziplock plastic bag and hammer the stack flat, though that will tear individual leaves apart, making the final product not be whole leaf tea. One of the benefits of micro-batch production is the attention one can give the individual leaf: almost entirely whole leaf teas are easy to make. The goal of this stage of the process is to transform the leaves from their newly picked velvety, waxy surface gleam to a moister and darker "muddled" appearance. This liberates the oxidases and peroxidases in the leaves to do their work, breaking down the leaf cell walls to make the flavors more bioavailable and starting the oxidative production of plant melanins from other pigments.

6a. For green tea, separate the muddled leaves from any remaining thick veins and roll into desired leaf shape (ball or twisted roll).

6b. For oolong (preferred for hot) or black (preferred for iced) tea, place a shallow layer in a suitably sized bowl and cover with a towel or clean dishcloth. Allow to darken and brown, mixing and separating the leaves several times an hour, until at the desired oxidation level. This ranges from an hour or so for light (10%) oolong to overnight for black (fully oxidized) tea. I find that our tea leaves take a couple hours to reach 10% oxidation but the reactions then speed up, so more frequent checking may be required to freeze oxidation at midrange oolong stages.

7. Fry tea leaves in a dry, non-oily frying pan or wok on medium heat, turning continuously, until the steam production slows and the leaves begin to crisp. Any temperature above 92 C will inactivate the polyphenol oxidases and stop browning due to intrinsic leaf enzymes, but you also will want to stop microorganism growth from causing further fermentation. For greener teas, you will want the leaves to be raised to somewhat above the boiling point (105 C or so), or else the tea may continue to darken in storage. Avoid cooking the tea by heating to temperatures above this as that will degrade flavor.

Alternatively, spread on a cookie sheet and bake in a preheated 215 degrees F (just above boiling point) oven for 15 minutes (oolong and black tea). A convection oven has a benefit of doing much of the dehydration at this stage, if you do not intend to roll the leaves further. For green tea that is to be rolled after baking, it is best to bake for only 5 minutes, to keep more water in the baked leaves (the Japanese process for green tea steams rather than dry heats the leaves to keep the water content higher for rolling).

8. Wash hands again. If desired, roll the leaves to compact them prior to drying. I often leave this step out, but if you plan to drink serial brewings of hot tea from the same leaves, tight rolling at this stage slows the first steeping and may make the second steeping a bit stronger.

9. Place back in the dehydrator and dehydrate at the "vegetable" setting (about 55 C) for a few hours or overnight. You want the tea extremely dry to prevent mold from ruining the tea in storage. This is also where keeping hands clean will pay off in shelf life.

10. Store in a tin or ziplock. I label the package with the packing date so as to use older product first. Enjoy the tea!

BioRxiv Weekend Review: Dealing with Complexity in Patterns of individual variation in visual pathway structure and function in the sighted and blind

When discussing complex systems like brains and other societies, it is easy to oversimplify: I call this Occam's lobotomy.

-- I. J. Good

Our BioRxiv preprint review this weekend is of an article which confirms the complexity of brain structure and its tendency to variation among different persons. The article shows that individual differences rule the type and location of brain adaptations that occur to visual loss, though the directions of that adaptation seem to stay the same for a given visual system variant. Perhaps those adaptations occur differently in different blind individuals because of preexisting individual differences in the affected visual systems. The authors may have found reason to take Good's warning to heart.



Patterns of individual variation in visual pathway structure and function in the sighted and blind

AUTHORS: Karl Aguirre, Ritobrato Datta, Noah Benson, Sashank Prasad, Samuel G Jacobson, Artur V Cideciyan, Holly Bridge, Kate Watkins, Omar H Butt, Alexsandra S Dain, Lauren Brandes, Efstathios Gennatas

doi: http://dx.doi.org/10.1101/065441


Many structural and functional brain alterations accompany blindness. In normally sighted people, there is correlated individual variation in some visual pathway structures. Here we examined if the changes in brain anatomy produced by blindness alter this pattern of variation. We derived eight measures of central visual pathway anatomy from an MPRAGE image of the brain from 59 sighted and 53 blind people. These measures showed highly significant differences in mean size between the sighted and blind cohorts. When we examined the measurements across individuals within each group, we found three clusters of correlated variation, with V1 surface area and pericalcarine volume linked, and independent of the thickness of V1 cortex. These two clusters were in turn relatively independent of the volumes of the optic chiasm and lateral geniculate nucleus. This same pattern of variation in visual pathway anatomy was found in the sighted and the blind. Anatomical changes within these clusters were graded by the duration of blindness, with those subjects with a post-natal onset of blindness having alterations in brain anatomy that were intermediate to those seen in the sighted and congenitally blind. Many of the blind and sighted subjects also contributed BOLD fMRI measures of cross-modal responses within visual cortex, and a diffusion tensor imaging measure of fractional anisotropy within the optic radiations and the splenium of the corpus callosum. We again found group differences between the blind and sighted in these measures. The previously identified clusters of anatomical variation were also found to be differentially related to these additional measures: across subjects, V1 cortical thickness was related to cross-modal activation, and the volume of the optic chiasm and lateral geniculate was related to fractional anisotropy in the visual pathway. Our findings show that several of the structural and functional effects of blindness may be reduced to a smaller set of dimensions. It also seems that the changes in the brain that accompany blindness are on a continuum with normal variation found in the sighted.

Lava Flow Videos

The Pu'u o'o vent of the Kilauea volcano continues its long-lived, 32-year and current eruption. Recently, the past summer, the flow has once again been mostly southward, and is now within the far southeastern border of the Hawai'i Volcanoes National Park. The flow is accessible on foot or mountain bike-then-foot combination, though it is a 10 to 12 mile round trip. The route from the parking lot area takes you 5 miles into the old flow on a pleasantly smooth, mountain bike accessible gravel emergency road followed by a half mile or so (less soon, as the flow moves) on rough, glassy and irregular older pahoehoe lava surfaces. Then, after the visit with the lava, back the same way.

It is well worth the hike if you come here. Bring lots of water with you for the hike. While we were there yesterday morning, two other hikers told us they had taken a frying pan and insulated mittens and had cooked their breakfast eggs and toast on the cooling lava surface.

Some videos below, from July 16 this past week:

An alternative to Kim's physicalism

In his book Physicalism, or Something Near Enough , Jaegwon Kim says: The final picture that has emerged is this: P is a cause of P*, wi...