Estimated water activity
The guidance water activity (aw) range shown with every filling, including its confidence level, the guidance shelf-life reference and contributing factors.
What it is
The Estimated water activity is a guidance aw range that AreaCacao computes for every filling from its formulation, nutritional composition and an inference of the solutes present. Water activity measures the free water available in the product: it is the physicochemical factor that most strongly drives microbial growth and therefore shelf stability.
Unlike a lab measurement, this estimate is deterministic and for guidance only: it uses no AI credits and is always expressed as a range with a confidence level, never as an exact number or a shelf-life promise.
Where it appears
- On the Filling formulator result screen, right below the physicochemical balance, as a card with the range, confidence and guidance shelf-life reference.
- On the Validation tab of any saved recipe (
/validation), as a compact block under the score. - On the recipe's printable sheet and PDF, right below the header (see Print recipe).
On the formulator card and in the recipe panel you can open View factors / View aw breakdown for the full analysis. The printed sheet doesn't include that breakdown.
In caramel and pâte de fruit, water concentrates as they cook, so the real aw is set by the finished product, not the raw formula. On the result screen, the card then shows We need a process data point with a production guide and, below it, the question Have you cooked it yet?: enter the Final °Brix or the final weight (g) (one of the two is enough; °Brix is more reliable) and the range is calculated on the spot.
What it shows
- aw range — e.g.
0.83–0.98. It is deliberately a range (not a point) because it builds on inferred data. The narrower it is, the more reliable. - Confidence level — High, Medium or Low confidence, depending on the quality of the available data (ingredient water, sugar profile, process data).
- Guidance shelf-life reference — the period the course aw table gives for the estimated range (see the next section).
- Factors that influence aw — which solutes and components push aw up (Raises aw, e.g. a fruit purée) or down (Lowers aw, e.g. sucrose, glucose, sorbitol), with their relative magnitude.
If the recipe has an instrument-measured aw, it is shown labeled as Measured aw and takes priority over the estimate.
Guidance shelf-life reference
AreaCacao looks up the aw in the course shelf-life table and shows the matching period. The lookup is the same on the Formulator card, in the recipe panel and on the printed sheet or PDF.
| aw | Reference period |
|---|---|
| 1.00 – 0.95 | 72 hours |
| 0.94 – 0.91 | 7–14 days |
| 0.90 – 0.87 | 14–30 days |
| 0.86 – 0.81 | 30–45 days |
| 0.80 – 0.76 | 60 days |
| 0.75 – 0.65 | 3 months (90 days) |
| 0.64 – 0.60 | 6 months |
| 0.50 or lower | 1 year |
How to read it:
- The bounds are inclusive exactly as written and the aw is not rounded. Values that fall between two bands (for example, 0.51 to 0.59) have no period: you'll see "the table has no reference for this value".
- Since the estimated aw is a range, there is a period only if the whole range falls within a single band. If it spans bands, the line says "the estimated range spans several bands of the table, so there is no single period". The app never picks the longest period.
- If you have a measured aw of the finished product, it is looked up separately and shown on its own line: "Indicative reference from the course table, based on the measured aw of the finished product: …".
- Underneath, it always says: "Real shelf life depends on the process, packaging and storage: measure the aw of the finished product and run tests."
- On the card and in the panel, if there is neither an estimate nor a measurement, no shelf-life line is shown. The printed sheet does show one: it says "there is no valid aw to look it up with".
- If you change ingredients, proportions or process, the reference is recalculated with the recipe's aw as it now stands.
This is the only period the Formulator gives. The master chocolatier's notes never give shelf-life or storage periods: if a tip includes one, the app doesn't show it, including in recipes you had already saved and on the recipe's public page. Process times (for example, rest for 24 hours) are kept. Separately, the recipe header on the result screen gives a single storage guideline, the same for every family: "Storage: at room temperature, between 16 and 18 °C".
How to read it
- Use it as a technical signal to compare iterations: lower the free water or raise the sugars and watch the range move. It's ideal for iterating before you produce.
- A high range (plenty of free water, typical of ganaches and fruit fillings) leads to short reference periods in the table; lowering the free water or adding humectants moves it toward longer bands.
- A high, narrow range with high confidence lets you trust the reading more; a wide range or low confidence means data is missing: treat it only as an approximation.
Supported families
The estimate is available for ganache, truffle, caramel, pâte de fruit and praline / gianduja. For other types you'll see the "Not available for this type yet" message.
Warnings you may see
The breakdown transparently flags when a value has been inferred rather than read from the ingredient record. For example:
- The glucose syrup profile (DE) was inferred.
- The fruit sugar profile was inferred.
- Couverture sugar availability was inferred by category.
- Missing °Brix or final weight; for cooked recipes the range is wider.
- Actual aw must be measured on the finished product to validate shelf life.
These warnings aren't errors: they explain why the range is wide and which data would narrow it.
What it is NOT
- It is not a measurement. It's a deterministic physicochemical model (multi-solute Norrish equation) over partially inferred data.
- It promises neither shelf life nor food safety. The table period is a guidance reference, not a guarantee. To validate safety, shelf life, technical labeling or commercial production, make the recipe and measure aw with a water-activity meter.
- It is not an exact number. It's always a range with confidence.
How to improve accuracy
Add the data the model is inferring: the purée °Brix, the syrups' DE profile, the process water loss (for cooked recipes), the actual pH and, above all, a batch aw measurement for calibration.