Formulating Zero-Sugar Carbonated Soft Drinks with High-Intensity Sweeteners
Zero-sugar carbonated soft drinks (CSDs) are sensory engineering projects. When you remove sucrose or HFCS, you lose not only sweetness, but also body, flavor lift, aroma carry, and the “rounding” that sugar provides. High-intensity sweeteners can rebuild sweetness—yet they bring challenges: sweetness timing, bitter/metallic notes, and stability constraints.
This technical guide focuses on how to design a sweetener system (often blended) that delivers a clean sweetness curve, good aftertaste control, and robust manufacturing performance for cola and fruit flavored CSDs.
A practical formulation workflow
Start with your target sweetness experience, then pick sweeteners and acids that deliver the right timing, cleanliness, and stability—while keeping manufacturing simple and repeatable.
Define the target profile
Sweetness intensity, onset, linger, and how carbonation and acidity shape perception.
Understand key sweeteners
Strengths, weaknesses, and where each sweetener typically works best in CSDs.
Blend for curve & cleanliness
Why blends outperform single sweeteners: curve shaping, aftertaste control, robustness.
Acid & flavor design
Citric vs phosphoric systems, fruit flavor brightness, cola balance, and sweetness perception.
Stability & preservation
pH control, benzoate/sorbate logic, and practical processing notes for syrup and finished drink.
Troubleshooting
Fix bitter notes, thin mouthfeel, “hollow” flavor, and sweetness drop over shelf life.
Define the target sweetness profile
The best sweetener system is the one that matches your brand’s sensory identity. Before you pick ingredients, define what “success” tastes like.
Think in 4 phases
- Onset: how fast sweetness appears
- Peak: maximum perceived sweetness
- Decay: how quickly sweetness fades
- Linger: the tail after swallowing
Sugar has a “balanced” curve; many HIS have slower onset or longer linger (and can feel “artificial” if uncontrolled).
CO₂ changes perception
Carbonation increases bite and perceived acidity, suppresses some sweetness, and can amplify bitter notes. Evaluate sweetness systems at the target carbonation level, not only in still syrup samples.
Practical tip: panel both still and carbonated samples to separate sweetener issues from CO₂ effects.
Plan “sugar replacement effects”
Sugar contributes viscosity, mouth-coating, and flavor roundness. Zero-sugar CSDs often taste “thin” or “hollow” unless the flavor system and acid balance are tuned for sugar-free.
In CSDs, you usually solve this with flavor architecture and acid choice—not heavy hydrocolloid use.
A simple target brief (what to write down)
- Style: cola / lemon-lime / orange / mixed fruit
- Sweetness intensity: “equivalent” to 8–11 °Brix sugar reference (choose your benchmark)
- Curve: fast/medium onset, short/medium linger, clean finish target
- Acid system: citric-driven (fruit) or phosphoric-driven (cola), or blend
- Constraints: storage temperature, shelf life, packaging (PET/can), and market preferences
Understand the main high-intensity sweeteners used in CSDs
Each sweetener has a different sweetness curve, taste signature, and stability behavior. In zero-sugar soda, you typically use blends to “engineer” the final sensory experience.
Strengths, weaknesses, and typical roles
| Sweetener | Typical strengths | Common watch-outs | Where it shines |
|---|---|---|---|
| Acesulfame K (Ace-K) | Fast onset, good top-note lift, synergistic with other HIS | Can add bitter/metallic edge at higher use; needs balancing | Fruit CSDs, lemon-lime; as a “curve starter” in blends |
| Aspartame | Sugar-like sweetness character; smooth profile in many CSDs | Sensitivity to heat/time under certain conditions; manage syrup handling | Cola and classic “diet” profiles; often paired with Ace-K |
| Sucralose | Very clean sweetness at low use; strong sweetness impact | Can feel “sharp” or have lingering sweetness if overused; needs curve shaping | Fruit flavors, modern zero-sugar profiles; paired with Ace-K for balance |
Note: actual sweetness perception depends on acid system, flavor type, caffeine, temperature, carbonation level, and regional taste expectations.
Why blends work
Many HIS combinations produce sweetness synergy (more perceived sweetness than expected), allowing lower use levels and reducing aftertaste. Blends can also reshape onset and linger.
“Clean finish” is designed
Bitter/metallic notes are often a combination of sweetener signature + acid bite + flavor top notes. Use blends, acid tuning, and flavor masking to remove “diet cues.”
Manufacturing tolerance
A system that tastes great at bench scale can drift in production due to pH changes, syrup strength variation, or CO₂ variability. Blends typically give a wider “acceptable window.”
Blending strategies to match sugar-like sweetness
Think of blending as curve engineering: one sweetener provides fast onset, another provides body/roundness, and a third may provide clean impact or cost optimization.
Aspartame + Ace-K
A common approach for cola-style profiles. Aspartame provides a sugar-like character while Ace-K boosts onset and top-note sweetness. Sensory tuning often focuses on reducing metallic edge and controlling linger.
Sucralose + Ace-K
Often used for fruit CSDs and “cleaner” sweetness perception. Ace-K helps onset while sucralose provides strong sweetness impact. Tuning often focuses on controlling sharpness and long sweetness tail.
Curve balancing
For challenging profiles, three-part systems can reduce the dose of any single sweetener and improve mouthfeel perception. The goal is not complexity—it’s a wider sensory “sweet spot” during shelf life.
A fast bench trial plan (low effort, high signal)
- Pick a sugar reference: make a carbonated reference at your target sweetness level (your internal benchmark).
- Choose 6–10 blend points: vary ratios while keeping perceived sweetness roughly constant.
- Test in carbonated form: evaluate onset/linger and off-notes under CO₂.
- Stress test: hold samples warm for a short period (e.g., accelerated check) to observe drift tendencies.
- Lock the curve: finalize ratio first, then adjust total sweetness and flavor architecture.
Best practice: train the panel to score (1) onset, (2) peak sweetness, (3) bitter/metallic, (4) lingering sweetness, (5) overall similarity to sugar reference.
Chasing sweetness with one sweetener
Over-dosing a single HIS often creates a “signature” aftertaste. Instead, blend to reach the target sweetness with lower individual doses, then use flavor and acid tuning to create fullness and a clean finish.
Acid and flavor design: the hidden engine of “sugar-like” taste
In CSDs, acid does more than set pH—it shapes brightness, bite, flavor release, and sweetness perception. Matching the acid system to the flavor style is a major lever for zero-sugar success.
Citric / malic logic
Citric acid delivers bright “top” sourness; malic can add a smoother, longer sourness impression that can support fruit depth. The right balance can reduce the need to over-sweeten.
Too much bite can expose sweetener aftertaste—acid tuning is an aftertaste control tool.
Phosphoric balance
Phosphoric acid delivers a different “bite” and dryness that suits cola profiles. In zero-sugar colas, sweetness curve and acid dryness must be balanced carefully to avoid a thin or harsh finish.
Build fullness without sugar
Sugar-free drinks often benefit from adjusted flavor layers (top/mid/base), modulation of cooling or citrus notes, and careful use of bitterness to avoid “hollow” impressions.
Sweetness isn’t only “sweetener dosage”
If the drink tastes less sweet than expected, check acid level, CO₂, and flavor top notes before increasing sweetener. Over-sweetening is a common path to lingering sweetness and a “diet” finish.
Stability and preservation in zero-sugar CSDs
A stable zero-sugar CSD requires control of pH, sweetener handling in syrup, hygienic processing, and (where used) correct preservative logic. Even when carbonation provides some protection, shelf-life design is still a system decision.
pH is a safety and flavor lever
pH affects preservative effectiveness, microbial risk, flavor brightness, and sweetener perception. Control pH with consistent acid dosing and good mixing practice.
Also control measurement: define temperature and method (pH meters drift; CO₂ affects readings if not managed).
When benzoate/sorbate makes sense
Many CSDs rely on low pH and good hygiene; some markets and formats use preservatives for additional safety margin. Preservative choice and dosing should follow your pH target and microbial risk assessment.
Always validate local regulations, product type, and target market expectations.
Don’t damage your sweetener
Some sweeteners are more sensitive to high heat or prolonged holding. Manage syrup preparation temperature, holding time, and order of addition to reduce drift and protect taste.
Production controls that protect flavor consistency
- Water quality: control hardness and off-notes (water impacts perceived sweetness and bitterness).
- Mixing order: dissolve acids and salts fully before adding sensitive components; avoid local high concentrations.
- Temperature discipline: avoid unnecessary heat exposure during syrup prep.
- CO₂ control: keep carbonation level consistent—small changes shift sweetness perception.
- Packaging: protect aroma and reduce oxygen pickup to prevent flavor flattening.
A zero-sugar CSD design checklist you can reuse
The point is not a “universal recipe” (every brand and market differs). Use this as a structure for your internal formulation sheet.
Zero-sugar carbonated soft drink – internal formulation sheet
1) Target sensory profile
- Style: (cola / lemon-lime / orange / mixed fruit)
- Sweetness benchmark: (choose sugar reference)
- Curve target: (onset / peak / linger)
- Finish target: (clean / slightly dry / round)
2) Sweetener system (high-intensity)
- Primary sweetener: (e.g., sucralose or aspartame)
- Secondary sweetener: (e.g., Ace-K for onset)
- Blend rationale: (curve + aftertaste control + robustness)
- Sensory risks to watch: (metallic, bitter, lingering, sharpness)
3) Acid system
- Acid type: (citric / malic / phosphoric / blend)
- Target pH range: (define)
- Bite/brightness target: (high / medium / low)
4) Flavor system notes
- Top notes: (citrus, cola top)
- Mid notes: (fruit body, spice)
- Base notes: (cola base, vanilla notes)
- Masking strategy: (if needed)
5) Manufacturing controls
- Syrup preparation temperature and hold time limits
- Mixing order and QC checkpoints
- Carbonation target and tolerance
- Packaging and oxygen pickup control
6) Shelf-life checks
- Sensory at: (0 / 2 / 4 / 8 weeks or internal schedule)
- Sweetness drift check
- Aroma loss / off-note emergence check
In practice, your sweetener supplier and flavor house often collaborate on the final curve + flavor pairing. A controlled template helps you run faster trials and document decisions for repeatability.
Troubleshooting common zero-sugar CSD problems
Most issues are “system” problems: sweetener ratio + acid + flavor + CO₂. Use targeted fixes instead of simply adding more sweetener.
Bitter/metallic edge
- Reduce reliance on one sweetener; increase blend synergy
- Check carbonation bite (CO₂ may be amplifying the edge)
- Re-tune acid level/type; excessive bite exposes off-notes
- Adjust flavor top notes and masking strategy
Lingering sweetness / “diet” finish
- Rebalance the sweetener ratio to shorten the tail
- Increase “onset” component and reduce “linger” component
- Adjust acid dryness/brightness for a cleaner finish
- Consider flavor base notes to add roundness (reduce perceived tail)
Thin / hollow taste
- Rebuild flavor architecture (mid and base notes)
- Check acid balance (too sharp can feel thin)
- Ensure sweetness peak is not too narrow (curve shaping)
- Validate water quality (hardness and off-notes can flatten body)
Sweetness drops over shelf life
- Check syrup preparation temperature and holding time
- Validate pH control and storage conditions
- Review oxygen pickup (aroma loss can mimic “less sweet”)
- Confirm CO₂ retention (lower CO₂ can change sweetness perception)
Harsh bite / too sour
- Reduce total acid slightly and re-evaluate sweetness (don’t chase with more sweetener)
- Switch or blend acid types (brightness vs rounded sourness)
- Check carbonation target and pouring temperature
- Adjust citrus top notes that may be intensifying sourness
Flavor feels “flat”
- Check aroma loss and packaging oxygen pickup
- Review flavor dosage and top-note strategy
- Ensure acid profile supports flavor release
- Confirm sweetener curve is not masking aroma (over-linger can dull perception)
Change one variable at a time
When troubleshooting, adjust one lever at a time (sweetener ratio, total sweetness, acid level/type, CO₂, or flavor architecture). Multiple simultaneous changes make it hard to learn—and slow down development.
References worth keeping in your formulation folder
Use these as high-level anchors for additive terminology and permitted-use discussions. Always follow destination-market rules and customer requirements.
GSFA (food category permissions)
Codex GSFA provides food category guidance that many technical teams use as a baseline reference.
EU additive framework (overview)
For projects targeting EU markets, align labeling conventions and additive permissions with EU requirements.
Purity & identity references
Customers may cite compendial references for purity criteria and analytical methods.
Important disclaimer
This article provides general technical guidance for formulation development and is not legal or regulatory advice. Sweetener permissions, labeling rules, and maximum use levels vary by market and product type. Always verify final compliance with the destination-market regulations and the brand/importer requirements.
Related Atlas Academy articles
Build a complete beverage formulation toolkit: acidulants, stability, pulp/cloud control, and preservation.
Using Citric and Malic Acidulants in Beverage Flavour Design
How acid choice shapes brightness, sourness timing, and flavor release in beverages.
Managing pH and Shelf-Life in Low-Calorie Beverages
pH control, buffer logic, and shelf-life considerations for low-calorie and zero-sugar drinks.
Sweetener Systems for Energy Drinks and Sports Beverages
Sweetener system design for fast sweetness, low calories, and aftertaste control.