In this LAB note
Question · Hypothesis · Method · Results · What Failed · What We Learned · What Changed at MOMS
Question
How much nutritional quality does a fresh, whole-food shake actually lose after 24 hours in the refrigerator, and does it still taste and perform like a same-day shake?
Hypothesis
We expected some vitamin C loss over 24 hours, but hypothesized that headspace and air exposure, not elapsed time itself, would be the dominant factor, meaning storage method would matter more than the 24-hour mark itself.
Method
Published research on fresh vegetable and fruit smoothies gave us a starting range. A study on red fresh vegetable smoothies with extended shelf life (Journal of Food Science and Technology) found that vitamin C degradation during cold storage depended heavily on processing and packaging conditions rather than time alone. A related study on plant and vegetable juice storage found that vitamin C content in blended drinks can drop by 10-15% within just the first few hours at refrigerator temperature, with degradation rate driven by oxygen exposure, light, and temperature, and that mild heat-treated smoothies held at 5C degraded roughly half as fast as identical smoothies held at 20C. We ran our own 24-hour shelf test using six of our shake formulas, split into a sealed condition (filled to the top of an airtight container, no headspace) and an unsealed condition (loosely capped mason jar with visible airspace). We measured vitamin C content via lab assay at 0, 6, 12, and 24 hours, and ran a 24-person blind taste panel comparing fresh shakes to their 24-hour sealed counterparts.
Results
Across the published literature, vitamin C loss in refrigerated blended drinks over roughly 24 hours ranges from near 0% up to about 17%, with oxygen exposure consistently identified as the biggest driver of loss, more so than time or even temperature within a normal refrigerator range. Our own assay landed inside that range but skewed low for the sealed condition: 9% vitamin C loss at 24 hours when sealed with no headspace, versus 21% loss in the loosely capped jar with visible airspace over the same 24 hours, more than double the loss from headspace alone. In the blind taste panel, 19 of 24 tasters could not reliably distinguish a fresh shake from a 24-hour sealed shake; most of the people who did notice a difference described it as "slightly less bright," not spoiled or off.
What Failed
The loosely capped mason jars with visible airspace consistently tested worse across every metric, higher vitamin C loss, more noticeable flavor drift in the taste panel, and in a few cases visible separation. Time alone wasn't the main variable; the air trapped in the container was doing most of the damage.
What We Learned
A shake made today and refrigerated properly is very close to a shake made tomorrow morning, nutritionally and in taste, but "properly" specifically means minimizing airspace, not just refrigerating it. The 24-hour mark itself isn't a meaningful nutritional cliff; the way the shake is sealed is.
What Changed at MOMS
Our storage guidance now specifically tells customers to fill containers to the top and seal tightly rather than just "refrigerate within 24 hours." We treat headspace, not time, as the variable that actually matters.
References
1. Red fresh vegetables smoothies with extended shelf life as an innovative source of health-promoting compounds. Journal of Food Science and Technology, 2016. https://doi.org/10.1007/s13197-015-2143-2 2. Stability of Vitamin C Content in Plant and Vegetable Juices under Different Storing Conditions. Applied Sciences (MDPI), 2023.
Keep reading
Previous experiment
Not sure which shake fits you? We match the formulation to your body type.
Find your body type