# Split Tea Brewing - Background ## Decent Profiles/Coffee Inspiration Got curious about this after seeing the video demonstrating Decent's [tea portafilter profile](https://www.youtube.com/watch?v=Dod23uBSdJM&t=299s). Taken at face value, they're not doing anything with pressure except using it to actuate the valve, and they claim that they are increasing extraction while reducing bitterness by doing multiple short infusions, inspired by gongfu style brewing. The premise is essentially that desirable compounds are extracted more quickly and less desirable compounds are extracted more slowly. In other words, by steeping in short bursts, gongfu brewing doesn't just divide the tea into different slices but actually avoids ever(?) extracting some of the things that come out in a longer western-style tea brew. (This also sort of resembles Lance Hedrick's ["percolative immersion"](https://www.youtube.com/watch?v=aR3tgBsSwmM) (coffee) video which is essentially just doing two separate immersion steps. Another interesting reference point is [Emi Fukahori's](https://europeancoffeetrip.com/emi-fukahori-world-brewers-cup-champion/) competition coffee brewing method using valved brewers and varying temperatures to target specific flavors.) I don't know how true this is but it does seem easy enough to replicate without a ton of specialized apparatus. Simply do several short steeps and decant them into the same container, preferably insulated. ## "Stacked" Gongfu Brewing Googling around, it looks like some folks who do gongfu style tea brewing refer to basically this practice as "stacking." It looks like folks mostly do this for convenience rather than anything else, and indeed, my interest also comes in significant part from the fact that most of the time I would much rather drink one 500mL tumbler of tea than 5 100mL cups etc. Some links: - [Reddit post testing stacked versus western-style](https://www.reddit.com/r/tea/comments/ublcb4/putting_stacked_infusions_vs_one_long_infusion_to/). The OP does not specify the length of the stacked infusions. - Stacking for convenience in preparing large batches: - [Reddit](https://www.reddit.com/r/tea/comments/5hdytn/suggestions_for_gong_fu_tea_with_a_large_group_8/) - [Reddit again](https://www.reddit.com/r/tea/comments/b77iko/comment/ejrszcv/?utm_source=reddit&utm_medium=web2x&context=3) - [Red Blossom](https://redblossomtea.com/blogs/red-blossom-blog/8-tips-for-brewing-multiple-infusions) specifically suggests this as a method for reducing bitterness - This [stackexchange](https://cooking.stackexchange.com/questions/107398/why-are-multiple-infusions-of-tea-better-than-one-large-one) answer just came up due to the name of the website, lol, but it is perhaps relevant anyway Some of these discussions refer to stacking as a way to average out the infusions but don't seem to get into targeting different flavors with different timings. However, I haven't gone over them in fine detail because I don't really enjoy poring over reddit threads. ## Split Brewing I initially tried brewing in even 45 second chunks, trying to get something like the Decent profile linked above that would provide a good balance. I found it tended to be too much on some teas and not enough on others. Then I tried shortening the initial steeps and adding one or two longer steeps at the end. Basically what this is doing is targeting different flavors with different lengths of infusion, and then using the number of infusions of each length to vary the relative strength of those flavors. I think of this kind of analogy to [split contrast darkroom printing](https://www.ilfordphoto.com/split-grade-printing/) in which you use different contrast filters to isolate parts of your print to dodge and burn etc., rather than just exposing the entire print at one best compromise contrast grade. I've tried to look for info on what flavors are associated with what compounds in tea and more importantly the relationship between time and extraction for those compounds. There's not much information beyond "more longer more bitter", and what more there is is mostly related to scientific studies to inform commercial extraction of flavor concentrates. [This one](https://www.sciencedirect.com/science/article/pii/S0023643822009070) is the most interesting I found, particularly that "umami" flavors that are associated with improved taste are extracted more efficiently at low temps (opposite of other compounds which extract more at high temps) and that their extraction drops quickly over time. Their optimal method for extraction is more like percolation, but I have yet to figure out how to efficiently and cheaply percolate tea at home. Where I'm at so far is mostly using 5 infusions of equal size, with the first 3-4 infusions being short (30s) and the last 1-2 being long (60s-120s), and a ratio of usually 4:1 or 3:2 of short infusions to long infusions. - Infuse and decant 4 times at 30s, then once at 60s - Infuse and decant 3 times at 30s, once at 60s, once at 120s The short early steeps tend to be more mild, floral, and/or sweet. (Depending on the tea) The longer steeps are where astringency and bitterness come in. We're varying the ratio of tea brewed in those steps to change the balance of the final beverage. Bitterness and astringency are associated with oversteeped tea, so it might seem better to do all short steeps (approximating percolation) but for me at least the results can feel unbalanced especially on teas that have a more subtle flavor to begin with. I think there's a _right amount_ of bitterness and astringency that is desirable to hit, at least for my preferences. Both the long and short steeps contribute to the overall body and mouthfeel, but I think without _any_ longer steps the body of the final beverage tends to be too thin. I don't think there's anything magical about the specific numbers I'm using, I'm just aiming for recipes that will be relatively easy to do, relatively easy to repeat, and will give me enough good-tasting tea to fill my tumbler up. If I could figure out more precisely when in the sequence I'm exhausting the good-tasting stuff targeted by the shorter infusions, or how long it takes to hit my desired ceiling of astringency and/or bitterness on the long infusions, without doing expensive science, then I might end up with quite different numbers. ## Possible Other Ways to Profile - Temperature - It's conventional wisdom to brew oolong/green teas at lower temps. This isn't necessarily [considered the best practice by experts](https://www.youtube.com/watch?v=XQI2xpXkJCc) in all cases, but [that extraction study](https://www.sciencedirect.com/science/article/pii/S0023643822009070) makes me wonder what you would get if brewing first at 80c and then later at a higher temp, instead of or in addition to splitting the infusion times. - My initial basic testing with low-temp (80c) brewing is that it does indeed work well for extracting the umami stuff without bitterness, but that the resulting brew is flatter than I would prefer. I also think that sweeter flavors benefit from higher temps. - Percolation Instead of Serial Immersion - Percolation extraction would probably be more efficient and possibly be easier as well, but I just haven't figured out a good way to do it yet. - Tea Dose vs. Time - I don't know what would happen if you were to stagger your tea input instead of your water input. I imagine it would depend on how much what's in the solution matters versus what's in the leaf. ## Process ### My Tools - Zujirushi water boiler set to 208 (brewing temp will be lower, any sort of kettle should be fine as long as you can get the temp to be vaguely consistent) - I dispense the water out of the Zujirushi into a vacuum flask to pour out of, for convenience. If you're using a kettle this is not needed - Tea brewing device. I'm using a plastic bottom-dispensing tea brewer with built-in mesh screen, but any teapot or even just a cup should work as long as you can pour into and out of it reasonably quickly and the leaves stay in it. - Scale to weigh tea and to weigh the hot water as it's added. - Weighing the tea will be most accurate since different leaf styles can have quite different volume vs weight - Volume measurement would be fine for the water but you wouldn't want to try to measure the volume _in the brewing device_ because as the tea leaves rehydrate they'll take up a different amount of the volume. Plus some brewing devices may have a bit of mechanical retention. - Timer (in my case, it's built into the scale) - Vacuum tumbler into which the tea is decanted and kept at a reasonably stable temperature - Optional: Separate non-insulated cup for letting the tea cool to taste - Optional: Thermometer for checking brewing temp ### Process - Optional: Preheat brewer - I've stopped doing this with my plastic brewer because as far as I can tell, the stuff we want during the short steeps would not necessarily benefit from the highest temps possible. I'm pulling water out of my Zujirushi boiler at 92c (on the highest temp setting) and seeing temps of 82-85c in the brewer. - Preheating will be more beneficial if your brewing device is made of, say, thick ceramic - Optional: Pre-rinse (few seconds) - Dealer's choice whether to do this or not. I think it's generally not necessary. - Begin steeping - Optional: Separately decant a small amount of the tea at some or all steps to taste and compare to the combined beverage. You can then adjust the number/duration of long steeps to taste. If doing this, try to cool the tea down a bit as drinking temp impacts taste significantly. - Once all steeps are complete, stir to make sure everything's evenly mixed - After brewing, tea may continue to gain strength as tea particles in the beverage continue to be extracted; straining through a paper filter might change this, but I don't know whether I'd even consider that desirable. But it's definitely something to be aware of especially if tasting mid-process in order to make corrections on the fly. ## Patterns Here are some split steeping patterns that all seem to kind of work to varying degrees and/or for different teas. These are all based on putting 500g total into the steeping vessel, which is a pretty good amount for drinking out of an 18 ounce vacuum tumbler. (Brewed tea yield is obviously less than water input due to water being retained in leaves.) There are some practical limitations on the ratio of tea to water within each steeping step. 6-8g of tea to 100g of water for looseleaf tea seems to be near a limit as it will be hard at higher ratios to get good contact on all the leaf area. Smaller leaf sizes allow for more flexibility. However, I have not yet tried grinding a full leaf tea to see if it has negative impact on flavor. Variables being targeted: - Short Steep Duration: The shorter, the more we exclude bitterness/astringency and maximize savory/floral flavors. - (Tentative): Medium Steeps: I think on _some_ teas, sweetness tends to extract more at around a minute. The tricky thing about trying to quantify this is that the the actual point for this I think will vary a lot from tea to tea, from well inside the short steep to well inside the long steep window. I think sometimes sweetness peaks somewhere in the 45-60s range. - Long Steep Duration: The longer, the more we include bitterness/astringency and body - Ratio of short to long steep volume: Balance of flavors - Total contact time: Longer total contact time increases overall strength and body Tuning - If output is bland, decrease S:L ratio - If output is salty, decrease S:L ratio - If output is harsh, increase S:L ratio or decrease time of long steeps - If output is thin, increase total contact time - If sufficient patience is available, do a salami test to adjust timing on short and long steeps - Number of steeps: For a more delicate or reserved tea, try using fewer steeps. This may also require changing your dose/ratio. ### Pattern Chart | | # | Tea | Water per | Steeps | Steep Dur | S:L | T. Time | Notes | | | ---- | --- | ----- | --------- | ------ | -------------------------------- | --- | ------- | --------------------------------------------------- | --- | | | A | 6-8g | 100g | 5 | 45 | | 225 | Too light on greener teas, too heavy on darker | | | | B | 6-8g | 100g | 5 | 4x30, 1x60 | 4:1 | 180 | Pretty balanced | | | | B2 | 6-8g | 100g | 5 | 4x45, 1x90 | 4:1 | 270 | Untried | | | Pull | C | 6g | 50g, 100g | 9 | 8x15 50g, 1x60 100g | 4:1 | 210 | Nerf harshness that emerges early | | | Pull | C2 | 6g | 80g, 100g | 6 | 5x15 80g, 1x60 100g | 4:1 | 160 | Similar to C but more practical, lower strength | | | Push | D | 6-8g | 100g | 5 | 3x30, 1x60, 1x120 | 3:2 | 300 | ==To push milder teas. My fav when it works== | | | Push | D2 | 6-8g | 100g | 5 | 3x30, 2x60 | 3:2 | 210 | ==Similar to D but more forgiving== | | | Push | D3 | 6-8g | 100g | 5 | 3x30, 1x90, 1x180 | 3:2 | 360 | Definitely a bit more western but can still balance | | | Pull | E | 6g | 110g, 60g | 5 | 4x30 110g, 1x60 60g | 7:3 | 180 | Untried: should nerf harshness that emerges late | | | Push | F | 10g | 100g | 3 | 1x30, 1x60, 1x90 | 1:2 | 180 | ==Concentrated black tea for latte== | | | Push | G | 6g | 100g | 5 | 2x30, 1x60, 1x90, 1x120 | 2:3 | 330 | Majority long steep | | | Push | G2 | 6g | 100g | 5 | 1x30, 2x60, 1x90, 1x120 | 1:4 | 360 | This is actually getting into western ratio | | | | H | 8-10g | 125g | 4 | 2x30, 2x60 | 1:1 | 180 | For less durable teas fewer steeps may be better | | | | H2 | 8-10g | 125g | 4 | 2x30, 1x45, 1x60 | 1:1 | 165 | This may give more sweetness | | | | I | 6-8g | 75g, 125g | 4 | 1x30 100g, 2x 45 150g, 1x90 100g | 4:1 | 210 | Adding extra vol in sweetness zone | | Pattern A is kind of a dead end. I used 45s to try to get a compromise infusion of one length, but I didn't love the result. So far my favorite result has been Pattern D on Smooth Water Baozhong, but I think for many teas Pattern B is closer to the sweet spot. Very pleased with pattern D on Plum Blossom Alishan as well. The less harsh the tea is the more we can get out of it, basically. D2 works well on teas that can be more harsh, while D3 pulls out just a little bitterness from teas that might have none at all on D. Pattern C minimizing brew time for the majority of the volume, but the smaller water volume on the short steps means that leaves may not be fully covered through the process. It's also a real pain in the ass to do 9 separate steps. I suspect that whatever we're targeting in the short steeps is getting exhausted somewhere in that process and from then on we're basically just diluting. C-2 or E should be more practical but I haven't tried them yet. I haven't tried to add more gongfu style incremental increases in time on the short steeps because I don't think e.g. 25/30/35 is significantly different from 30/30/30 in practice and the timing is annoying enough already. ## Patterns vs. Teas ### General notes - So far I've mostly tested on oolongs - Heavily roasted teas present a challenge because the roast flavors extract very easily, meaning that they can be harsh even on very short steeps - Teas with low astringencies can and should be pushed farther to get the best balanced flavor and the most body - Black teas can be brewed to avoid harshness, but the result will often seem off because it simply isn't what's expected. ### Specific Teas I've Tried | Vendor | Tea | Type | Style | Patterns | | --------------- | ----------------------------------------- | ------ | --------------------- | --------- | | Floating Leaves | 2022 Winter Smooth Water Baozhong | Oolong | Baozhong | D | | Floating Leaves | Dark Roast Tie Guan Yin | Oolong | Heavy Roast | C | | Floating Leaves | Nantou Four Seasons | Oolong | | B | | Floating Leaves | Alishan Black | Black | "High mt. red oolong" | B, D2 | | Floating Leaves | Dong Ding Traditional A | Oolong | Dong Ding | B | | Floating Leaves | Plum Blossom Alishan High Mt. 2022 Winter | Oolong | High mt. | D, D3 | | Floating Leaves | Pearls of Dew | Oolong | Med. roast | D2 | | Floating Leaves | Diva High Mt. Oolong 2022 Winter | Oolong | "Trad high mt." | D | | Floating Leaves | Winter Shan Lin Xi | Oolong | | D3 | | Bird Pick | Decaf Organic Maofeng Green | Green | Maofeng | D2, C2 | | Bird Pick | Decaf Royal High Mountain Oolong | Oolong | Medium roast | G, D2, D3 | | Kong Mountain | 2021 First Prize Lapsang Souchong | Black | Lapsang Souchong | | | Kong Mountain | 2018 Gu Mo Raw Puerh Dragon Ball | Puerh | Sheng | | | Kong Mountain | 2020 Autumn Bai Hua Tan | Puerh | Sheng | | | Red Blossom | Tung Ting, Mi Xiang | Oolong | Bug-bitten | | | Upton | C02 Decaf Assam | Black | Assam blend | B, D2 | | PG Tips | Decaf | Black | | B | | Old Ways | 2022 Cousin's Bei Dou | Oolong | Wuyi | H | | Old Ways | 2021 Zuhuo Bei Dou | Oolong | Wuyi | | | Old Ways | 2022 Jin Xuan | Oolong | Wuyi (w/milk tea v.) | | # Experimentation ## Side by Side Comparison of Patterns To do: B vs D/D2/D3 vs H/H2 ## Further testing on times between 30s and 60s What do we gain from adding in 45s steps? ## Disordered Timing With apologies to gongfu drinkers everywhere, as well as to the tea which did not deserve this. 2022 Winter Smooth Water Baozhong steeped gongfu style (6g/100mL) but with chaotic timing. My takeaway here is that doing longer steeps earlier in the process is not beneficial and it's easier to extract what you want if you do it in order of short to long. | Time | Notes | | ---- | --------------------------------------------------------------- | | 15s | Sweet, thin, floral | | 60s | Sour, moderately astringent, medium body, slight mineral | | 30s | Just thin (deliberately testing this after a longer extraction) | | 60s | Mineral, slightly thin, slightly floral | | 180s | Mineral, slightly astringent, slightly savory | However, I accidentally did 60/30/30/60/60 on Pearls of Dew and got a quite sweet result. So maybe it's worth experimenting a bit further with initial steep length. ## Salami Test Todo. Probably start with slightly lower tea to water ratio to accommodate sampling, otherwise by the end the water may not cover the leaves. So, maybe like 150mL of water to 6g; it'll be weaker but relative differences should be generalizable still. The other option is to do several small doses independently, but I'm not sure I trust my scale/measurement technique enough. One question is what intervals are relevant. Is starting at 15s early enough, or should I also be testing 5s or shorter? | Time | Notes | | ---- | ----- | | 5s | | | 10s | | | 15s | | | 30s | | | 60s | | | 90s | | | 120s | | | 240s | | ## Stacking Progress Test After each steep, pour some of the combined, stirred beverage at that point into each of five cups. This will give a sense of where the drink is at after each step. ## Half Salami Test The primary benefit of the salami in tea brewing is to determine the points in the steeping process where astringency and bitterness begin and where they exceed the desired intensity. So, it may be more beneficial to combine it with the stacking progress test like so: - Brew and stack short steeps - Perform salami test on a long steep at this point - 60s, 90s, 120s, 150s, 180s - If feeling ambitious, could also add in tea from the short steeps in a 3:2 or 4:1 ratio ## Ratio Splitting Need to experiment with different ratios for the early and later steeps -- what is the impact of using a lower or higher ratio on the relative extraction of the desired flavors in the various phases? The concept here is the same as the Kasuya 4:6 coffee technique, where increasing the volume of the second pour increases sweetness -- however, there is a key different between coffee and tea extractions, other than the obvious one of grinding vs. not grinding, and that is bloom. In essence, the bloom phase with coffee creates entirely different dynamics in the first pour versus other pours. Tea does not have that. _But_ there is another aspect here that is shared between both. Increasing the ratio increases extraction efficiency. (However, it also adds dilution.) Short ratios will be strong but will extract less from the leaf as the solvent loses efficiency. So in principle, we could do one short phase to pull off some of the acid, do one high volume phase in the sweetness zone (45-60s at least on several teas) and then do one or more additional short, low volume phases to dial in bitterness to taste. Example: - 50g 30s, 100g 60s, 50g 120s - 100g 30s, 50g 60s, 50g 120s - 50g 30s, 50g 60s, 100g 120s Running this test with smooth water baozhong does give a bit more sweetness with higher volume in the 60s range. Comparing to the same total volume but with 50g 30s / 50g 60s / 50g 60s / 50g 120s (i.e., splitting the 100g 60s into two 50g) gives a weaker result with the split ratio but less astringent; hard to say whether the result seems to be sweeter or not. ## Overall Temp Lowering the temp does a good job reducing bitterness and astringency, but also results in overall flatter, weaker tea when using the same timing. Using longer steeps compensates to _some_ extent, but I think some flavors don't want to extract at lower temps. When experimenting with the Birdpick decaf green, lower temps did not extract sweet flavors, in particular. ## Split Temp Todo. Test same dose for 30s at 75, 85, 95C? Need to let all cool well before testing. Also need to test, if practical, doing short and long steeps at different temps. Use, e.g., 85C for the short steeps and 94C for the long steeps. Shouldn't be too bad, just need to set aside some water in thermos while letting some cool in a normal vessel. Kind of a pain to do in daily drinking though. The opposite test is probably also worth trying. It may even be beneficial to get weirder and try brewing short and long steeps at low temp and middle (45-60s) steeps at high temp (for sweetness). ## Hot-to-Cold Brewing? What happens if you start with a short hot brew (or brews) and then chill it and put it into cold brew mode? E.g. maybe a short brew over ice or just into cold water, and then also chuck the leaves in there and put it in the fridge. ## Chilled Extraction In coffee, this is done with percolation methods (espresso, pourover) over top of a whiskey stone or into a chilled cup. it's not immediately clear what the best way would be to adapt that to s brewing in an ice water bath, which seems suboptimal ## Filtration Todo: Compare e.g., Pattern D as is versus the same filtered through a paper filter to remove tea particles ## Grinding Tea Todo, need a grinder for this. - Compare impact on extraction between full leaf and ground tea at various steep times - Compare different grind sizes There are three possible advantages to grinding tea: 1. Increased extraction speed for efficiency 2. More freedom with high doses of tea (just fitting the leaves into a smaller amount of water) 3. More even extraction due to more normalized particle size There are two main possible disadvantages: 1. Negative changes to flavor profile 2. Unavoidable harshness from overextraction ## Tea Percolation It would be interesting to try something more in the vein of percolation either for all of the brew or part of it. However, pourover equipment, especially all the cheap kinds, is using the ground coffee itself for the majority of its flow control. So, trying to brew good tea in a V60 or whatever would most likely result in drawdown times of a few seconds. Non-starter. Obviously one could try grinding tea to the same dimensions and...see what happens. Or brew with CTC or matcha in a filter, but I don't think most off-the-shelf CTC tastes great no matter what you do with it, and I'm not sure how matcha would behave. Good quality looseleaf tea already tastes good; breaking the leaves up certainly increases extraction, but also according to at least some of the research I skimmed, might change the profile of what's extracted (even when comparing the same tea). There are a some brewing devices available with variable-rate valves controlling flow. They're mostly designed for slow-drip cold brew which would probably be too slow a flow rate, but some are intended to be dual-use pourover brewers, like the Goat Story Gina (can't believe it's called that). (See [here](https://europeancoffeetrip.com/emi-fukahori-world-brewers-cup-champion/)) Or [one of these](https://www.amazon.com/Yama-Glass-CD-8-silver-Coffee/dp/B00T24PQ54/). However, these are kind of spendy since I have no idea whether they would (a) work at all and (b) be an improvement over doing a handful of short steeps. It might also be tricky to standardize flow rate without a scale that can do flow rate. The cheapest one of those seems to be the Timemore Black Mirror Basic Pro. ## Tea Latte This seems to more or less work for a large latte that fits in an 18 ounce tumbler. Great results with Upton's Extra Bergamot Earl Grey, decent results with decaf assam. - 10g tea, 100g water, 30/60/90 - 30/90/120 works better for decaf assam - Microwave 200g oat milk for 1-2 min, froth Todo: Try 5x60g steeps with 5g dose in pattern D3. # Reference: Gongfu Temps and Ratios ## Mei Leaf dude: | Tea | g/100mL | temp c | temp f | | ------------ | ------- | ------ | ------ | | White | 4 | 90 | 195 | | Green | 4 | 80 | 175 | | Green-Oolong | 6 | 95 | 205 | | Dark Oolong | 6 | 95 | 205 | | Black | 4 | 95 | 205 | | Raw Puerh | 5 | 95 | 205 | | Ripe Tea | 5 | 99 | 210 | ## Teahouse Santa Fe [Link](https://teahousesantafe.com/blogs/news-resources/your-guide-to-gongfu-brewing) | Tea  | Water Temp | Amount (g/100 mL) | 1st infusion (seconds) | Additional infusion (seconds) | Avg. # of infusions | |----------------------|--------------|-------------------|------------------------|-------------------------------|---------------------| | White | 85°C (185°F) | 4 | 10 | 10 | 6 | | Green | 80°C (176°F) | 4 | 10 | 5 | 6 | | Oolong (strip) | 95°C (203°F) | 6 | 20 | 5 | 8 | | Oolong (ball rolled) | 95°C (203°F) | 8 | 20 | 5 | 8 | | Black | 95°C (203°F) | 5 | 15 | 5 | 8 | | Puerh (raw) | 95°C (203°F) | 5 | 10 | 5 | 15 | | Puerh (ripe) | 99°C (210°F) | 5 | 10 | 5 | 15 | # Reference: Western Temps and Ratios (Divide by 1.77 or multiply by 56.5 going from 6 ounces to 100 mL) ## Upton: | Tea | g/6oz | g/100 mL | temp c | temp f | Steep Time | | ----------------------------------- | ----- | -------- | ------ | ------ | ---------- | | Tie-Guan-Yin | 2.25 | 1.27 | 87.8 | 190 | 4-5 | | Four Season Spring Dong Pian Oolong | 2.25 | 1.27 | 87.8 | 190 | 4-6 | | Formosa Jade Oolong Supreme | 2.25 | 1.27 | 82.2 | 180 | 3-4 | # Grandpa Ratio - [3g per 8oz](https://www.youtube.com/watch?v=Gk9AGqXGkaY) / 3:237 or about 1:79 # ISO 3103 - [Wikipedia](https://en.wikipedia.org/wiki/ISO_3103) - 2 grams of tea (measured to ±2% accuracy) per 100 ml boiling water is placed into the pot. - Freshly boiling water is poured into the pot to within 4–6 mm of the brim. Allow 20 seconds for water to cool. - Brewing time is six minutes. # Research - Wu Mountain "Science Behind a Bold but Balanced Tea Extraction", [Part 1](https://wumountaintea.com/2020/07/30/a-hot-take-on-tea-extraction-science-part-1/) and [Part 2](https://wumountaintea.com/2020/07/31/the-science-behind-a-bold-but-balanced-tea-infusion-part-2/) Discusses relative extraction speeds of aminos (savory, fast-extracting, extracts at low temps, not abundant in tea) and polyphenols (bitter, slow-extracting, needs higher temps, abundant in tea) - [Tea Epicure: Chemical Compounds in Tea](https://teaepicure.com/tea-chemistry/) - [Tea Epicure: Kinetics of Steeping Tea](https://teaepicure.com/kinetics-of-steeping-tea/) - [Research summary on commercial extraction](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4444893/), not readily usable - [Extraction kinetics of tea aroma compounds as a function brewing temperature, leaf size and water hardness](https://onlinelibrary.wiley.com/doi/full/10.1002/ffj.3571) - Experiment used green tea - Leaf size is more important the shorter the infusion, temperature is more important the longer the infusion, in determining the amount of volatile compounds extracted. - "At the lower temperature of 60°C, the extraction is slow, with minor differences in the aroma profile during the first 1.5 min of infusion. At the other extreme, the infusion at 80°C reached in only 30 s extraction time the same volatile composition as an infusion at 60°C after 1.5 min or at 70°C after 1 minute. " - "The fact that samples infused at different temperatures within one leaf size were clustered in different groups when the raw intensity was used but they all belonged to the same group when normalized intensity was considered indicates that a change in temperature resulted in different overall amounts of volatile compounds being extracted—higher extraction efficiency with higher temperatures—however, the VOCs had similar extracted volatile profiles (‘more of the same’). Only change from full to broken leaf leads to different extraction profiles and, therefore, different dynamics of the extraction. In other words, breaking the leaves not only increased the extraction rate, it also changed the extraction dynamics of compounds." (tl;dr: temperature did not change which VOCs were extracted at what levels, but leaf size did) - "It can be clearly seen that the differences between both full and broken leaves were significant only at the beginning of extraction. While the average content of dimethyl sulphide seems still higher also at longer brewing times, after 1.5 min of infusion, those differences were no long significant." - [Effects of dynamic extraction conditions on the chemical composition and sensory quality traits of green tea](https://www.sciencedirect.com/science/article/pii/S0023643822009070) - Green tea - Note that again this is aimed at commercial extraction rather than tea brewing. - "high umami" extraction at low temp (50c) with continuously pumped water. - Graphs concentration versus time at different temps for total solids, amino acids, polyphenols, gallated catechins, non-gallated catechins, and caffeine. Graph shows that amino acid extraction has the opposite relationship to temp as all the other stuff? And also drops off more quickly over time. - They report "The bitterness and astringency taste intensities increased with extraction time, whereas the umami intensity and the overall acceptability score decreased." - Larger leaf size correlated with less bitterness/more umami/more acceptability - "umami intensity of tea infusion can be improved by increasing the tea-to-water ratio in the early extraction stage." - Their study is interested in the effect of varying flow rate on the final extraction, with reduced flower rate as the extraction goes on. However, this is for commercial-oriented extraction processing over a period of 40 minutes, so no saying if this bears in any way on brewing tea to drink. - Flow rates used in their testing range from 10.5-19.5 mL/min - [On the relative extraction rates of colour compounds and caffeine during brewing, an investigation of tea over time and temperature](https://www.degruyter.com/document/doi/10.1515/chem-2022-0158/html?lang=en) - Only really interested in relative caffeine strength versus color. - [Current extraction, purification, and identification techniques of tea polyphenols: An updated review](http://agri.ckcest.cn/file1/M00/0F/EC/Csgk0GG6oQOAW9F-ACP9D1tEgk8174.pdf) - [Barista Hustle research summary on water hardness and tea](https://www.baristahustle.com/blog/water-chemistry-for-tea/) interestingly harder water may yield less bitter tea - [Mei Leaf video on varying/targeting temperature](https://youtu.be/rD7bnull_yY) includes brewing into a chilled vessel -- similar to some of the "chilled extraction" stuff seen in coffee. Seems like a pain in the ass to use a water bath, but so does trying to extract over a whiskey stone when doing an immersion brew. # Water ## EBMUD Specs [Annual Water Report](https://www.ebmud.com/water/about-your-water/water-quality/water-quality-report-english) ![[Pasted image 20230123201423.png]] ## Tea Association targets ![[Pasted image 20230123201827.png]] ## Specialty Coffee Association targets ![[Pasted image 20230123201646.png]] ## Teacurious Recipe https://www.teacurious.com/water-recipe