# R&D RADIO: How Water Activity Keeps Shelf-Stable Food Safe, Crunchy, and Fresh

- Show: [The Startup CPG Podcast](https://hardwarepodcasts.com/podcast/the-startup-cpg-podcast)
- Published: 2026-10-26
- Length: 32m
- Episode: 391
- Page: https://hardwarepodcasts.com/podcast/the-startup-cpg-podcast/2026-10-26-r-d-radio-how-water-activity-keeps-shelf-stable-food-safe-crunchy-and-fresh
- Listen: https://share.transistor.fm/s/38f2bfa9

## Summary

Zachary Cartwright, Principal Food Scientist at AQUALAB by Addium, explains water activity (a_w) as the capacity of water to drive biological, chemical, and physical changes in food products. He details how a_w above 0.6 enables microbial growth, while specific thresholds cause textural issues like caking in powders or sogginess in snacks. The conversation covers the difference between moisture content and water activity, the use of moisture sorption isotherms to predict shelf life, and how sustainable packaging with different water vapor transmission rates impacts stability. Cartwright advises brands to access testing via universities or labs, but emphasizes that in-house meters with direct sensors and temperature control are ideal for quality control.

## Outline

1. Introduction: Zachary Cartwright and AQUALAB
2. Defining Water Activity and the 0.6 Microbial Threshold
3. Critical Water Activities: Texture, Caking, and Stickiness
4. How Water Activity Testing Works and Speed of Readings
5. Moisture Content vs. Water Activity and Sorption Isotherms
6. Product Formats: Beverages, Frozen Inclusions, and Condiments
7. Packaging Decisions and Sustainable Material Challenges
8. Accessing Testing: Labs, Universities, and In-House Meters
9. Scaling Production: Incoming Ingredients and Large-Scale QC

## Topics

- [Materials & manufacturing processes](https://hardwarepodcasts.com/topic/materials-and-processes)
- [Quality & yield](https://hardwarepodcasts.com/topic/quality-and-yield)
- [Packaging design](https://hardwarepodcasts.com/topic/packaging-design)
- [Prototyping & iteration](https://hardwarepodcasts.com/topic/prototyping)
- [Scaling production](https://hardwarepodcasts.com/topic/scaling-production)

## Most relevant to

early-stage companies

## Mentioned

- AQUALAB (company)
- Addium (company)
- Washington State University (other)

## Citing this page

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