Stress-Load Index
Open data · version 0.1.0 · 2026-10-09 · CC BY 4.0
How much caffeine or alcohol is in one everyday serving, each number taken from its USDA FoodData Central record, and the caffeine half-life the SnapStress app uses to estimate how much is still active at your bedtime. Estimates for a typical adult — general wellbeing, not medical advice.
| Item | Serving | Caffeine, mg | Alcohol, g | Record |
|---|---|---|---|---|
| Coffee, brewed | 1 cup (8 fl oz, 237 g) | 95 | — | FDC 171890 |
| Espresso | 1 shot (1 fl oz, 29.6 g) | 63 | — | FDC 171891 |
| Black tea, brewed | 1 cup (8 fl oz, 237 g) | 47 | — | FDC 173227 |
| Green tea, brewed | 1 cup (245 g) | 29 | — | FDC 171917 |
| Cola | 1 can (12 fl oz, 370 g) | 33 | — | FDC 174852 |
| Energy drink | 8 fl oz (240 g) | 91 | — | FDC 174821 |
| Dark chocolate, 70–85% cacao | 1 oz (28.35 g) | 23 | — | FDC 170273 |
| Milk chocolate bar | 1 bar (1.55 oz, 44 g) | 9 | — | FDC 167587 |
| Wine, table | 1 glass (5 fl oz, 148 g) | — | 15.4 | FDC 173185 |
| Beer, regular | 1 can (12 fl oz, 356 g) | — | 13.9 | FDC 168746 |
| Spirits, 80 proof (gin, rum, vodka, whiskey) | 1 shot (1.5 fl oz, 42 g) | — | 14.0 | FDC 174815 |
Method
Each value is the record's amount per 100 g × the serving weight ÷ 100, rounded to a whole milligram of caffeine or a tenth of a gram of alcohol. Every serving is one of the record's own household portions. A validator rebuilds every row from verbatim lines of USDA's SR Legacy download and fails the release on any row without a record, a source link or a date.
The bedtime estimate
Caffeine still active = the serving's caffeine × 0.5hours until bed ÷ 5. The 5-hour half-life is the mean for healthy adults stated by the Institute of Medicine's committee report Caffeine for the Sustainment of Mental Task Performance (2001, chapter 2, read 2026-10-09), which also gives the individual range: 1.5 to 9.5 hours (pregnancy, oral contraceptives and smoking among the reasons). Yours may be shorter or longer. Example: a coffee (95 mg) six hours before bed leaves about 41 mg active.
Not in this release: light from a phone screen at night. No primary source we have read states a quantity the index could carry per row, so the row stays out until one does.
Download
- export/stress-load.csv — one row per item
- export/stress-load.json — the full file, with sources and the half-life
- export/datapackage.json — Frictionless Data Package (sizes and hashes)
Licence and credit
Our layer — the selection, servings, rounding and the bedtime model — is CC BY 4.0: credit "SnapStress Stress-Load Index, snapstress.com/data". USDA FoodData Central values are in the public domain (CC0 1.0, as FoodData Central states on its API guide).
Changelog
0.1.0 · 2026-10-09 — first release: 11 items (coffee, espresso, black and green tea, cola, energy drink, dark and milk chocolate, wine, beer, spirits).