For hot-brewed iced tea, brew black tea at double strength (21 g per liter), then pour it over its own weight in ice: the heat balance says 1,000 g of tea at 90 °C melts 1,000 g of 0 °C ice on the way to 5 °C. Assam, Ceylon and Nilgiri are the usual picks; a 2 L pitcher costs $4.05–$7.77 in leaf at catalog medians.
Iced tea fails in two ways: it comes out weak because the ice drowned it, or cloudy because the strong brew precipitated as it cooled. Both have numbers behind them.
This guide covers the brew methods vendors publish, the ice math, the chemistry of cloudy tea, and what each tea costs per pitcher in the Tea Explorer catalog, 7,306 teas from 40 vendors, fetched 2026-10-01. For overnight fridge brewing at about 10 g of green tea per liter (Kettl), see our cold brew ratios.
Four ways to brew iced tea hot
Every hot method does the same thing: brew strong, then dilute with ice or cold water.
| Method | Recipe | Dilution |
|---|---|---|
| Japanese style (Ippodo) | 10 g sencha, 210 ml boiling water, 60 s | Poured over a glass full of ice |
| Double strength (Harney & Sons) | Twice the tea for the same water | Poured over a tall glass of ice |
| Half hot, half cold (Smith Teamaker) | 1-quart sachet in 2 cups boiling water, 5 min | Topped to 1 quart with water, served over ice |
| Quarter hot (Luzianne) | 1 gallon bag in 1 quart boiling water, 3–5 min | Remaining 3 quarts of cold water |
| Flash chill (Rishi) | About 1.5 tsp per 8 oz, "slightly more" than hot | Poured over a pitcher of ice |
Ippodo states the logic plainly: the ice "dilutes the tea to the right strength, and quickly cools it off at the same time" (Ippodo). The ice is an ingredient. If you do not weigh it, the strength is a guess.
One lab comparison found hot brewing followed by ice extracted the most caffeine for green and black tea, more than hot or cold brewing alone (Lantano et al.). Cold water extracts less: at 10 °C for 1 hour, caffeine reached about 50% of an 80 °C, 2-minute infusion (Monobe).
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Flash-chill math: how much ice
The ice has to absorb the heat the tea gives up. Water's specific heat is 4.186 J per gram per °C (HyperPhysics), and melting ice takes 80 cal per gram (HyperPhysics), which is 335 J. Ice from a cold freezer must also warm to 0 °C first, at 2.05 J/g·°C (HyperPhysics).
The balance, for tea mass M cooling from T_hot to a final 5 °C:
ice grams = M × 4.186 × (Thot − 5) ÷ (335 + 2.05 × (0 − Tice) + 4.186 × 5)
For 1,000 g (about 1 liter) of hot tea:
| Tea temperature | Ice at 0 °C | Ice at −10 °C | Finished drink with 0 °C ice |
|---|---|---|---|
| 100 °C | 1,118 g | 1,057 g | 2,118 g |
| 95 °C | 1,059 g | 1,001 g | 2,059 g |
| 90 °C | 1,000 g | 946 g | 2,000 g |
| 80 °C | 882 g | 834 g | 1,882 g |
Computed from the HyperPhysics constants above; tea treated as water, no heat lost to the pitcher or air.
Three practical results:
- Equal weight of ice. Tea that leaves the pot at 90 °C needs almost exactly its own weight in 0 °C ice to reach 5 °C. That is why "double strength over ice" works: the melt doubles the volume and halves the strength.
- Colder ice, less dilution. Ice at −10 °C cuts the ice needed by 5%. The difference is small; weigh the ice instead of worrying about the freezer.
- Extra ice stays solid. Taking the same liter all the way to 0 °C melts 1,125 g. Any ice beyond that floats and keeps the drink cold. Real pitchers lose some heat to the glass and air, so a little less ice melts than the table says.
Check Ippodo's glass. The leaves hold about 4 times their weight in water (MAFF), so 10 g keep back 40 ml and about 170 ml of tea leaves the pot. If it pours at 90 °C, it melts about 170 g of ice for a 340 ml drink at 2.9 g of leaf per 100 ml. Our grams per cup guide compares that with hot ratios.
Why iced tea turns cloudy
Cloudy iced tea is "tea cream," the precipitate that forms as tea cools (Jöbstl et al. 2005). Two studies describe what is in it:
- Concentration drives it. A higher tea concentration starts creaming earlier and forms larger particles (Jöbstl et al.). A double-strength concentrate is exactly that condition.
- Theaflavins start it, caffeine fills it. Theaflavins start nanoclusters of about 3 nm, and caffeine fills the gaps (Jöbstl et al.). A 2024 study found proteins, caffeine and phenolics dominate cream formation, with caffeine–theaflavin complexes as the likely core (Chen et al. 2024).
- Calcium makes it worse. Calcium promoted creaming, and the authors list removing calcium as a way to reduce it (Jöbstl et al.). Hard tap water carries calcium; see our water guide.
The advice on cooling speed conflicts. Iowa State and Ohio State extension pages say to cool the concentrate gradually, adding cool water before ice, to avoid cloudiness (Iowa State, Ohio State). Rishi says the opposite, that rapid chilling "helps lock in brightness and clarity" (Rishi). We found no controlled study comparing the two. What the chemistry does support: keep the concentrate no stronger than you need, and use soft water.
Best teas for iced tea
Vendors that sell iced tea name the same origins. Smith Teamaker blends Assam and Ceylon for its iced tea and says these teas "don't get bitter, don't cloud" (Smith). Young Mountain Tea says Nilgiri teas "don't get cloudy as they steep, which makes them popular for high-end iced tea" (Young Mountain Tea). These are seller claims, not lab results. Our Assam vs Ceylon vs Kenyan guide covers how the origins differ.
For green tea over ice, Ippodo uses sencha at 10 g per 210 ml (Ippodo); Kettl does the same with hojicha at 10 g per 300 ml for 1 minute (Kettl).
Cost of a 2 L pitcher, made as about 1,000 ml of 90 °C concentrate poured over 1,000 g of ice. Hot water includes the extra the leaves soak up. Prices are catalog medians as of October 1, 2026:
| Tea | Leaf per liter of hot water | Steep | Hot water | Leaf | Ice | Median $/g (teas) | Leaf cost per 2 L |
|---|---|---|---|---|---|---|---|
| Assam | 21 g | 3–5 min, boiling | 1,092 ml | 23 g | 1,000 g | $0.18 (35) | $4.05 |
| Ceylon | 21 g | 3–5 min, boiling | 1,092 ml | 23 g | 1,000 g | $0.21 (17) | $4.89 |
| Nilgiri | 21 g | 3–5 min, boiling | 1,092 ml | 23 g | 1,000 g | $0.34 (8) | $7.77 |
| Sencha | 48 g | 60 s, boiling | 1,235 ml | 59 g | 1,000 g | $0.30 (54) | $17.71 |
| Hojicha | 33 g | 1 min, boiling | 1,154 ml | 38 g | 1,000 g | $0.29 (19) | $11.15 |
Sources: dose links in the table; steep times from Iowa State (black), Ippodo (sencha) and Kettl (hojicha); prices from the Tea Explorer catalog, 7,306 teas from 40 vendors, fetched 2026-10-01.
Assam is the cheapest pitcher at $4.05, Ceylon $4.89 and Nilgiri $7.77. The finished black pitcher holds 11.5 g of leaf per liter, close to the 10.6 g per liter of a Harney hot cup. Japanese-style sencha costs 4.4 times as much as the Assam pitcher, because Ippodo's ratio is a strong single-glass recipe. Price your own tin in the tea cost calculator or browse /teas.
Sweeten while the concentrate is hot. Rishi says to stir honey in "while the tea is still hot to help it fully dissolve" (Rishi).
Hot brew, cold brew and sun tea safety
Hot brewing is the safe default. The CDC and the National Tea Association recommend steeping at 195 °F for three to five minutes, which Iowa State Extension says is enough to kill potential microorganisms (Iowa State).
- Storage: do not hold brewed tea at room temperature for more than 8 hours, and drink refrigerated tea within three days (Iowa State).
- Cold brew: brew in the refrigerator, not on the counter. Ratios and times are in our cold brew calculator.
- Sun tea: it does not get hotter than 130 °F, which is not hot enough to kill bacteria, and a thick, syrupy brew can mean ropy Alcaligenes viscolactis (Ohio State).
Frequently Asked Questions
How much tea do I use for iced tea?
For black tea poured over ice, use double strength: about 21 g per liter of hot water, twice Harney's 10.6 g per liter hot dose. Japanese-style sencha is stronger, 10 g in 210 ml for 60 seconds. Cold brew green tea uses about 10 g per liter with no ice.
How much ice do I need to flash-chill tea?
About the same weight as the hot tea. By heat balance, 1,000 g of tea at 90 °C melts 1,000 g of 0 °C ice to reach 5 °C, or 946 g of ice from a −10 °C freezer. Add more ice than that and the extra stays solid.
Why does my iced tea turn cloudy?
It is tea cream: theaflavins and caffeine form particles as strong tea cools, and higher concentration and calcium make it start sooner. Use soft water and avoid over-strong concentrates. Vendors say Nilgiri, Assam and Ceylon teas cloud less.
What is the best tea for iced tea?
Assam, Ceylon and Nilgiri black teas are the common vendor picks for clear, smooth iced tea. At catalog medians a 2 L pitcher costs $4.05 with Assam, $4.89 with Ceylon and $7.77 with Nilgiri. Sencha and hojicha work for green iced tea but cost more per pitcher.
Is sun tea safe?
Sun tea does not get hotter than 130 °F, too cool to kill bacteria, according to Ohio State Extension. Brew hot at 195 °F for 3–5 minutes or cold brew in the refrigerator, and drink refrigerated tea within three days.
