Testing Sweet Products: How to Avoid Bias and Accurately Measure Consumer Acceptability

Reducing sugar content while maintaining consumer satisfaction is one of the key challenges facing food manufacturers today. Yet testing sweet products introduces very specific methodological pitfalls: the perception of sweetness is highly sensitive to how the samples are presented to consumers.

Recent scientific studies strongly confirm a reality that we’ve long observed in our Repères research protocols: the test design directly shapes the conclusions that can be drawn about the optimal sugar level of a formulation.

Why Direct Comparative Tests Systematically Favor "Sweeter" Products

In traditional comparative tests — where consumers taste two products simultaneously or a few minutes apart — the sweeter product is systematically favored.

Multiple studies across yogurt, chocolate‑flavored milk and soft drinks have shown that:

• As soon as a sugar difference is present, even small, the sweeter product gains an immediate hedonic advantage.
• This effect is amplified when tasting occurs on small sample sizes (e.g. sip tests like the famous Pepsi Challenge).

In other words: the closer the tasting, the more easily consumers detect sweetness differences — and the more they overvalue that sweetness in‑the‑moment.

In Real‑Life Use, Consumers Tolerate Much Higher Sugar Reductions

However, when tested without direct comparison — i.e. when each product is assessed in isolation — sweetness perception becomes far more flexible.

Some studies show that in monadic testing, sugar reductions of up to 25–30% in flavored dairy products can be introduced without significantly impacting overall liking.

Why? Because in real life:

• Consumers compare the reformulated product to their global memory of their usual product — not to a side‑by‑side sample.
• Differences in sweetness are not amplified by immediate contrast effects.
• Evaluation occurs on full portions, in a natural consumption context (time of day, meal context, accompaniments…).

The Industrial Risk of a Poorly Calibrated Protocol

When testing a lower‑sugar recipe directly against the current version, there’s a high risk of overstating the “lack” of sweetness — leading to conclusions that consumers will reject the reformulation, when in fact the product may be fully acceptable in real‑life use.

This may lead manufacturers to:

• underestimate feasible sugar reduction levels,
• unnecessarily limit innovation on nutrition‑related claims,
• distort R&D and formulation trade‑offs.

How to Secure Sweet Product Testing: Repères Recommendations

All these scientific insights fully align with the applied research expertise we bring to sugar‑reduction studies. At Repères, we consistently recommend:

1/ Sequential Monadic Home Use Tests

• One product tested per day, without direct confrontation.
• Each sample is evaluated independently, in the respondent’s natural usage context.

2/ Temporal Spacing to Neutralize Contrast Effects

• Respondents cannot directly compare sugar levels across samples.
• Evaluations reflect their own sensory thresholds relative to real‑world expectations.

3/ Integration of Emotional and Implicit Measurements

• Our tools (R3m, CATA modules) capture the emotional shifts induced by sugar reduction.
• We detect whether emotional engagement is compromised — well beyond simple liking scores.

In Summary, the test protocol is a strategic factor in accurately evaluating sweet products.

At Repères, our product tests are designed to solve the true challenges our clients face: achieving the right balance between nutritional innovation and consumer pleasure.

Discover the other articles in our product testing series:

Reco#1 At‑home vs in‑hall: Where to test for real consumer feedback?

Reco#2 Monadic or sequential: How to structure tests for reliable results?

Reco#3 Blind or branded: Are you testing the formula or the full offer?

Reco#4 Measuring what consumers feel… not just what they say

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