Full decant vs leaving a little water behind

[Lentil Asana]

Question or objective: settle a habit argument with cups rather than doctrine
Tea category: roasted oolong
Exact product: Cliff Lantern 2025 Shui Xian
Vendor: Red Pine Tea
Origin: Wuyishan, Fujian
Cultivar, if known: Shui Xian
Harvest season/year: spring 2025
Processing or roast: medium charcoal roast
Cake/batch number, if relevant: cake/lot noted above where applicable; otherwise N/A
Purchase/opening date: purchased 2026-05-20; opened 2026-07-20
Storage since purchase: sealed original pouch inside a dark cupboard
Style: gongfu
Vessel: porcelain gaiwan
Vessel material: porcelain
Nominal and actual filled capacity: 100 ml nominal / 90 ml filled
Filter or strainer: lid gap
Kettle: standard electric kettle + thermometer
Vessel preheated: yes
Dry leaf weight: 7.0 g
Water volume: 90 ml
Water temperature: 96°C
Water source or mineral profile: filtered tap water, 75 ppm
Rinse: 5-10 s where noted by the recipe; otherwise none
Infusion schedule: 8/10/12/18/25 s
Agitation: none
Was each infusion completely decanted?: full decant vs ~8 ml left between steeps
Aroma: similar
Sweetness: higher with full decant
Bitterness: higher when water left
Astringency: medium vs high
Body/texture: full
Flavour: roast, plum, mineral
Aftertaste: cleaner with full decant
Number of satisfying infusions: 7
Exact problem: testing whether leftover water meaningfully compounds extraction
Desired result: settle a habit argument with cups rather than doctrine
Variable changed: decant completeness
Previous value: leave ~8 ml
New value: full decant
Result: full decant reduced cumulative bitterness by steep four
Dry-leaf photograph: not attached yet
Liquor photograph: available in the author’s notes; not embedded in this archive
Wet-leaf photograph: available in the author’s notes; not embedded in this archive
Video if pouring or drainage is relevant: pour/drainage video described in the post; not embedded in this archive

I ran this as a comparison rather than two unrelated cups because memory is a terrible laboratory assistant. The main variable was decant completeness: leave ~8 ml versus full decant. Everything else was kept as close as I could manage.

The result so far: full decant reduced cumulative bitterness by steep four. I would be interested in reports from people who have repeated the same comparison, especially if you used similar water and vessel.

[Object Biography]

Controlled test
Direct recommendation: repeat the session with full decant.
Applies to: Cliff Lantern 2025 Shui Xian / roasted oolong in a setup close to porcelain gaiwan.
Evidence: firsthand ownership/use of both compared options.
Change: repeat the session with full decant.
Expected effect: the cup should move toward settle a habit argument with cups rather than doctrine if that variable is causal.
Observed result: full decant reduced cumulative bitterness by steep four.
Limitations: My result is from a small number of sessions, so treat it as evidence rather than law.
Commercial relationship: none.

[Civic Fish Stories]

Controlled test
Direct recommendation: repeat the same recipe on a second day.
Applies to: Cliff Lantern 2025 Shui Xian / roasted oolong in a setup close to porcelain gaiwan.
Evidence: controlled side-by-side use under matched conditions.
Change: repeat the same recipe on a second day.
Expected effect: a repeated result should be easier to trust.
Observed result: full decant reduced cumulative bitterness by steep four.
Limitations: This may not transfer to a heavier roast or a very different vessel size.
Commercial relationship: none.

[Lentil Asana]

Long-term report
Direct recommendation: weigh the actual filled water once.
Applies to: Cliff Lantern 2025 Shui Xian / roasted oolong in a setup close to porcelain gaiwan.
Evidence: firsthand long-term use of one side of the comparison.
Change: weigh the actual filled water once.
Expected effect: your ratio will become comparable with other reports.
Observed result: not tested on this exact setup yet.
Limitations: This may not transfer to a heavier roast or a very different vessel size.
Commercial relationship: none.

[Civic Fish Stories]

Controlled test
Direct recommendation: repeat the session with full decant.
Applies to: Cliff Lantern 2025 Shui Xian / roasted oolong in a setup close to porcelain gaiwan.
Evidence: side-by-side or repeated one-variable test.
Change: repeat the session with full decant.
Expected effect: the cup should move toward settle a habit argument with cups rather than doctrine if that variable is causal.
Observed result: not tested on this exact setup yet.
Limitations: Water chemistry may change the result, so I would not generalize this to every city.
Commercial relationship: none.

[Lentil Asana]

Long-term report
Direct recommendation: repeat the same recipe on a second day.
Applies to: Cliff Lantern 2025 Shui Xian / roasted oolong in a setup close to porcelain gaiwan.
Evidence: repeated sessions over time.
Change: repeat the same recipe on a second day.
Expected effect: a repeated result should be easier to trust.
Observed result: full decant reduced cumulative bitterness by steep four.
Limitations: My result is from a small number of sessions, so treat it as evidence rather than law.
Commercial relationship: none.

[Author]

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