Kirkland Green Tea: Complete Caffeine Guide

A typical 240 ml cup of brewed green tea — the closest match to Kirkland’s standard green tea — contains 28 mg of caffeine.

• 240 ml brewed green tea ≈ 28 mg caffeine (USDA FoodData Central).
• Bottled iced green tea servings (355 ml) often land near 45 mg caffeine — useful when estimating diet/bottled variants.
• Matcha (1 tsp) is stronger at 70 mg; concentrated cold-brew coffee can be >150–200 mg per 240 ml.
• FDA recommends a maximum of 400 mg/day for healthy adults; pregnancy guidance is ~200 mg/day (FDA/Mayo Clinic).

Green tea caffeine basics

“Green tea” in food databases and nutrition labels usually refers to a standard brewed infusion: 240 ml contains 28 mg (11.7 mg/100 ml) according to USDA FoodData Central. That is roughly one‑quarter to one‑eighth the caffeine of a typical 240 ml brewed coffee (96 mg) or a 250 ml energy drink like Red Bull (80 mg).

Caffeine in regular Kirkland green tea

Kirkland-brand loose leaf or tea-bag green tea sold in bulk is a brewed Camellia sinensis product; its caffeine should track the USDA value for brewed green tea: about 28 mg per 240 ml cup. Variability comes from leaf grade, water temperature and steep time: hotter water and longer steeps extract more caffeine.

Quantifying a typical serving

If you brew 240 ml (one U.S. cup) with a standard 2–3 minute steep, expect ~28 mg. Using the dataset comparisons below helps place that amount next to common alternatives.

Diet (bottled) Kirkland green tea — what to expect

Many retail diet/zero‑sugar bottled green teas use different extraction and sometimes added decaffeinated blends. There’s no Kirkland‑specific bottled value in public datasets, so use bottled iced tea as a proxy: 355 ml bottled iced tea ≈ 45 mg (dataset). That makes a 240 ml portion of bottled green tea roughly 30–35 mg, but treat that as an estimate until the product label or USDA entry is available.

Organic Kirkland green tea caffeine content

Organic certification affects farming practices, not intrinsic caffeine content. Organic green tea brewed to the same strength will contain the same 28 mg per 240 ml baseline. Differences arise from cultivar (sencha, gyokuro), leaf age and processing — not organic status.

Comparing Kirkland green tea to other drinks

Use this comparison to see where Kirkland green tea sits versus coffee, matcha, energy drinks and other teas.

What affects caffeine in a cup of green tea

• Leaf type: younger buds and stems can be higher (gyokuro vs bancha).
• Leaf amount: doubling leaf mass roughly increases caffeine proportionally.
• Water temperature and steep time: hotter/longer → more extraction.
• Bottle vs brewed: bottled iced teas often come from concentrated extracts or blends, changing mg per serving.

Half-life and how much caffeine remains after drinking

Population-average caffeine half-life is about 5.7 hours (peer-reviewed pharmacokinetics; commonly cited). That means ~69% remains after 3 hours, ~48% after 6 hours, ~33% after 9 hours and ~23% after 12 hours. Below are concrete examples using dataset doses.

Health, safety and timing vs sleep

Official guidance: FDA suggests up to 400 mg/day for healthy adults; for pregnancy clinicians and FDA commonly recommend limiting to ~200 mg/day; the American Academy of Pediatrics discourages caffeine for adolescents. A single 240 ml cup of Kirkland green tea at 28 mg is low relative to those limits, but cumulative intake from coffee, energy drinks and pills adds quickly.

For sleep, avoid significant caffeine within 6–8 hours of bedtime if you are sensitive; even green tea’s 28 mg can contribute residual stimulation because ~48% remains after 6 hours (roughly 14 mg in this example).

How to track intake precisely

If you drink multiple beverages (tea, coffee, energy drinks) or use concentrated matcha, track milligrams, not cups. CoffeeLog is a convenient way to log each serving and see daily totals against recommended limits. For packaged Kirkland iced or bottled teas, use the label’s mg or volume and compare to the tables above.

Sources and final notes

Caffeine amounts referenced are drawn from standard food composition entries (USDA FoodData Central) and beverage manufacturer disclosures included in the dataset. Safety recommendations cite FDA, Mayo Clinic and the American Academy of Pediatrics. This page is informational, not medical advice—consult your physician for individual guidance on pregnancy, anxiety, heart conditions or suspected caffeine overdose.