The short answer
Cold brew is leaf plus cold water plus time. Extraction runs slowly at refrigerator temperatures, so the bitter and astringent fraction of the leaf mostly stays behind while the sweet and aromatic fraction comes forward - the reason cold-brewed tea reads smoother than its hot-brewed twin. A common trade starting frame is about 1 gram of leaf per 100 ml of cold water, steeped 6-8 hours under refrigeration, adjusted by family and by lot: cut black teas run faster, tightly rolled oolongs slower, and fruit and herbal blends sit somewhere in between. Every figure here is a starting frame to be tuned by cupping on the actual lot, and the bottles that result are fresh products with a hold window, a label, and a discard rule.
Starting frames by tea family
| Family | Starting leaf rate | Refrigerated steep | Behavior |
|---|---|---|---|
| Green tea (sencha, jasmine) | 1 g / 100 ml | 6-8 h | Bright and low-bitterness; over-steeping is forgiving but not unlimited |
| Black tea (CTC, lemon black) | 1 g / 100 ml | 4-6 h | Cut leaf extracts faster; watch for heaviness at long steeps |
| Rolled oolong (Tieguanyin) | 1-1.5 g / 100 ml | 8-12 h | Granules open slowly; plan the long version overnight |
| White tea (silver needle) | 1-1.5 g / 100 ml | 6-8 h | Subtle; the cold version amplifies sweetness |
| Fruit and herbal blends | 1-1.5 g / 100 ml | 6-10 h | Sheets flag them as cold-brew friendly; color deepens with time |
The parameter sheets behind our lines flag some teas as explicitly cold-brew friendly - the lemon black tea and the fruit blends carry it in their own reference frames - and the rest are tuning exercises: brew a liter at the starting frame, taste at two hours, four, and overnight, and write down where the lot peaks. That number, not the table, is your recipe.
Batch size does not change the frame, only the arithmetic: the frame is a ratio, so a five-liter container is the one-liter recipe times five, weighed and logged the same way. Leaf cut does change it - the finer the particle, the faster the cold extraction and the earlier the peak, which is why bags and broken grades need watching an hour or two sooner than whole leaf. Fold both adjustments into the same log and the frame becomes property of the program rather than of whoever happened to set it up, which is what lets a second shift, or a second site, brew the same bottle.
Steep cold, hold cold
The food-safety version of this product is not optional, and it is simple. Steep under refrigeration, not on the counter: the refrigerated route removes the temperature-abuse window entirely, and venues that do short counter steeps are running a different risk profile that their own food-safety rules, not a blog post, should govern. Use filtered water with no off-odors, since cold brewing hides nothing - whatever the water smells like, the bottle tastes like. Steep in sanitized food-grade vessels with lids, keep the leaf fully submerged, and agitate once partway through for even extraction. Date and label every batch at the moment it goes in, with leaf grams, water volume, start time, and initials. Then set a hold window and a discard policy in writing before the first bottle is sold: an unpasteurized cold brew is a fresh product with a short life, and the honest rule is that when a batch cannot be dated, it cannot be sold. Local food regulations govern the details; the desk supplies lots and brew frames, and the program's HACCP-style habits are yours to write.
Bottling: clarity, sediment, holding
Three physical problems decide whether a bottled cold brew looks professional by day two. Sediment comes from leaf fines and from extraction continuing in the bottle; strain the finished liquor through a coarse filter and then a fine one, and pull the leaf exactly when the frame says stop. Cloudiness is mostly cosmetic - chilling a rich brew can haze it - and flavor is unaffected, so decide the policy and stop worrying about it. Dilution is the silent one: ice in the serving glass cuts the drink, so either brew the base stronger to compensate or serve bottled product over minimal ice. Many venues split the difference with a concentrate: double the leaf rate, hold the bottle, and cut with cold or sparkling water at the glass, which the iced lemon tea note works through in detail. Bottle cold, display cold, and keep the display out of direct light, especially for green teas whose freshness is the whole point of the bottle.
Which teas earn a cold line
A cold program does not need ten SKUs; it needs two or three that behave. The proven starters are lemon black tea, whose sheet calls for cold brewing outright, and the fruit blends, which hold color and aroma for days of service. Jasmine green tea cold-brews into a soft, floral bottle that converts customers who think they dislike green tea, and a rolled oolong gives the program a slow, deep option for overnight batches. Silver needle makes a delicate bottle worth featuring but not worth rushing. Whatever the lineup, brew each candidate both hot and cold during sampling, because lots differ: a tea that is charming hot can turn flat or sharp cold, and the desk cups cold candidates at cold frames before recommending them. Auditioning is cheap on this side of the menu - labeled liter batches brewed during prep hours, not experiments run in service - so treat new lots as weekly tastings rather than leaps of faith. Staff habits finish the job - one batch sheet per recipe, one discard rule per fridge, and a weekly taste against a kept reference bottle, the same calibration routine that keeps hot service honest.
Buying for a cold program
Tell the desk the end use in the first message: steeped-and-bottled, concentrate-and-cut, or brewed-to-order pitchers. The lot that suits each differs more than the category name suggests, and we coordinate samples from partner gardens and packing facilities that are cupped at cold frames before they are quoted. Ask for the per-lot brew sheet, confirm the validated numbers in writing per program, and expect the frame to be revisited at each harvest change - cold brewing forgives a lot, but it does not forgive two different lots under one recipe card. Start from the lemon black tea and fruit blend lines or the hospitality program page, and send the bottle concept through the quote form. For the water side of the same drink, see the water quality note; for service formats at volume, the restaurant cold brew note.