House Kombucha (F1 + Fruit F2)

A clean, bracing house kombucha: black-tea sweet tea fermented by a SCOBY to a tart, lightly vinegary F1, then bottled with fruit for a softly carbonated, fruit-perfumed finish. This is the workhorse recipe everything else in this section branches from.

Ingredients

1 Jar = a 1 L wide-mouth jar; 1 Crock = a 4 L crock or spigot vessel. Weigh the sugar and tea; measure starter by volume. The acidified starter is a safety control, not an optional flavoring — see the warning below.

F1 — sweet tea

Component	1 Jar (1 L)	1 Crock (4 L)
Non-chlorinated water	~850 mL	~3,400 mL
White granulated sugar	60 g	240 g
Loose black tea (or 2-3 bags)	6 g	24 g
Mature kombucha starter (15%)	150 mL	600 mL
Healthy SCOBY	1	1-2

F2 — fruit per bottle

Component	per 500 mL bottle
Finished F1 kombucha	~450 mL
Fresh fruit purée or 100% juice	30-50 mL (about 8-12%)
Optional extra sugar	3-5 g only if fruit is low-sugar

Yield

About 1 L finished kombucha per jar (less the 15% you reserve as next batch’s starter), or 4 L per crock — roughly two 500 mL F2 bottles per liter.

Calculated Values

Sugar concentration (F1 start): 60 g/L = 6% w/v; most is consumed by the endpoint.
Starting pH: 15% mature starter into sweet tea lands the start below 4.5 (target 4.2 or lower) — confirm with a meter. See /docs/calc-ph-safety.
Target finished pH (F1): 2.5-3.5.
F1 temperature + days: 21-27 °C / 70-80 °F, 7-14 days.
F2 temperature + days: 21-27 °C, 1-4 days sealed, to carbonation.

Readiness Window

F1: 7-14 days at 21-27 °C. Begin tasting and measuring pH around day 7. Warmer rooms finish faster; wide vessels finish faster than deep ones.
F2: 1-4 days sealed at room temperature, then chill.

Done-when (F1): pH reads 2.5-3.5 on a calibrated meter and the brew tastes pleasantly tart with only a faint sweetness. Done-when (F2): a sealed bottle feels firm and a test pour fizzes. Arrest by refrigerating at 2-4 °C, which slows the yeast and locks in the carbonation.

Brew and cool the sweet tea

Steep 6 g tea per liter in just-boiled water for 5-7 minutes, remove the tea, then dissolve 60 g sugar per liter. Top up with non-chlorinated water and cool to below 30 °C — hot tea will kill the SCOBY.

Acidify the start (safety step)

Stir in 15% mature kombucha starter by volume, then add the SCOBY. Measure: the start must read below 4.5 (target 4.2 or lower). This acid head-start is the primary hurdle against mold and pathogens.

F1 — aerobic acid build

Cover with tight-weave cloth and a band. Hold 21-27 °C for 7-14 days. Do not seal — the acetic-acid bacteria need air. A pale, smooth new SCOBY layer forming on top is normal.

Confirm the F1 endpoint by pH

From day 7, taste and measure. When pH is 2.5-3.5 and the brew is pleasantly tart, F1 is done. Reserve at least 15% (150 mL/L) as starter for the next batch before bottling.

F2 — bottle with fruit

Funnel kombucha into pressure-rated swing-top bottles with 8-12% fruit purée or juice, leaving 2-3 cm headspace. Seal and hold 21-27 °C for 1-4 days. Residual yeast ferments the fruit sugar in the closed bottle, trapping CO₂.

Burp, then chill to arrest

Burp bottles daily by briefly cracking the cap over a sink. Once firm and fizzy, refrigerate at 2-4 °C. Chill fully before opening so the CO₂ stays in solution and the bottle does not gush.

Variations / mix-ins

Green-tea base: swap black for green tea at the same 6 g/L for a lighter, faster brew.
Half-and-half F2: split a batch across several flavors — see kombucha flavors for ginger, berry, and hopped versions.
Continuous brew: in a spigot crock, draw off finished kombucha and top back up with fresh sweet tea at the same ratio, leaving the SCOBY and a large acid reserve in place.

Kombucha method

pH safety calculator