Comparing RA, RM, and GSG Stevia Grades: What the Purity Numbers Actually Mean
Comparing RA, RM, and GSG Stevia Grades: What the Purity Numbers Actually Mean
Blog Article
When a procurement team asks for "RA 97%" or "RA 98%" or "GSG 80%", they usually mean more than the number on the label. They need a stevia extract that delivers the right sweetness profile, fits the process, and can be approved with a current specification and lot documentation. The number is a starting point, not a decision.
This article walks through how the leading stevia grades — Rebaudioside A at 60%, 97%, and 98%, Rebaudioside M at 95%, and total steviol glycosides (GSG) at 80% — actually compare, what each grade can and cannot do, and how to set up a grade comparison that survives a third-party audit and a commercial launch.
## Start with the measurement, not the percentage
RA means Rebaudioside A, while RM generally refers to Rebaudioside M. GSG is commonly used for total steviol glycosides. These are not interchangeable purity statements. A product labeled RA 98% is targeting an RA assay; GSG 80% is normally describing the total glycoside content. The two numbers answer different questions about composition.
Before comparing offers, ask for the assay basis (as-is or dry basis), HPLC method, acceptance tolerance, and the chromatographic profile. A one-point difference between RA 97% and RA 98% is meaningful only when both suppliers use comparable methods and report on the same basis. This simple check prevents a low-looking quote from becoming an expensive reformulation.
## Use the grade matrix before requesting samples
| Requested grade | What it helps you evaluate | Evidence to request |
| --------------- | -------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------- |
| RA 60% | A less concentrated RA option where dosing room, cost-in-use, and flavor balance matter | RA assay and total glycoside profile, sensory sample, recommended dose, lot COA |
| RA 97% | A high-RA starting point for compact dosing and a clean, repeatable sweetness target | HPLC method and tolerance, chromatogram or profile, COA, equal-sweetness trial support |
| RA 98% | Very high RA concentration when the formulation and dosing system justify the tighter target | Proof that the 98% figure is comparable with the 97% offer, plus full commercial terms |
| RM 95% | A different glycoside identity and sweetness curve, often evaluated for a smoother taste direction | RM identity and assay basis, glycoside profile, sensory guidance, availability and price |
| GSG 80% | A total-glycoside specification that may provide a broader composition than a single RA grade | Definition of GSG, component breakdown, method, tolerance, representative COA |
The matrix is a screening tool, not a substitute for a specification. Confirm the exact requested grade, tolerance, and commercial availability in writing before treating any option as approved.
## Compare samples at equal perceived sweetness
Do not compare powders at the same weight. Prepare each grade to the same perceived sweetness against your control sweetener, then evaluate the finished product. Record the dose required, onset and linger, bitterness, cooling effect, acidity response, and any masking needed. For beverages, check clarity, sediment, and hot-fill or pasteurization behavior. For baked goods and confectionery, check bulk, browning, texture, and aftertaste after the full process.
Use coded samples and at least one repeat preparation. A grade that tastes better in water may not be the best choice after acids, flavors, proteins, fats, or heat are introduced. A targeted sample set built around the buyer's matrix produces more useful comparisons than five unstructured powders.
## Keep sweetness separate from sucrose functions
Stevia extract contributes intense sweetness, but it does not supply the bulk, solids, browning, humectancy, or crystallization behavior of sucrose. In a beverage, that may mean adjusting acid, flavor, and mouthfeel. In a baked product, a bulking system may be required. In confectionery, solids and texture usually need their own design.
This is why a high-purity grade is not automatically the right upgrade. RA 98% can reduce powder handling at a very low dose, while RA 60% may offer more dosing room. RM 95% may be preferred when the sensory target matters more than a familiar RA benchmark. The right comparison is total formulation cost and finished-product performance, not the highest purity number.
## Control dosing and premix handling
High-purity extracts can be difficult to weigh accurately in small pilot batches. Use calibrated scales, prepare a validated premix with a suitable copyright, and define a mixing order that prevents segregation. Record the actual active dose, not only the premix weight. At scale, confirm that the same method works across operators and equipment.
Ask the supplier for handling guidance, packaging options, and storage conditions for the selected grade. These details are part of supply reliability because a material that is technically compliant but hard to dose consistently can create avoidable batch variation.
## Build the approval file before the purchase order
- Current product specification with assay basis, method, and tolerance.
- Representative lot COA and the release tests used for shipment.
- Technical data sheet, safety data sheet, origin, allergen, and GMO statements where required.
- Microbiology, heavy-metal, and contaminant limits matched to the destination market.
- Packaging, shelf life, storage, MOQ, lead time, and change-notification expectations.
- Relevant certification scope and any customer-specific questionnaire responses.
Use the same checklist for every grade. It turns "RA 97% versus RA 98%" into a documented technical and commercial comparison instead of a marketing-number contest.
## Send an inquiry that produces a comparable quote
Tell the supplier the grade or grades under consideration, product matrix, target sweetness, expected dose, annual or trial quantity, destination, required documents, and decision date. If you are open to alternatives, state which variable is flexible: purity, sensory profile, lead time, or cost-in-use.
A useful reply identifies the exact grade, assay, tolerance, sample lot, specification, availability, packaging, MOQ, lead time, shelf life, Incoterm, and change-control terms. That response can be reviewed by R&D, QA, and procurement without translating a generic sales quote.
## Frequently asked questions
**Is RA 98% automatically better than RA 97%?**
No. The higher number may help a specific dosing or sensory target, but method comparability, get more info tolerance, taste, and cost-in-use decide whether it is better for your formula.
**Is GSG 80% the same as RA 80%?**
No. GSG generally refers to total steviol glycosides, while RA identifies one glycoside. Request the component profile before treating the grades as alternatives.
**Which grade should be sampled first?**
Start with the grade that matches your sensory and dosing objective, then include one adjacent benchmark. Confirm the current specification and propose a focused comparison.
**Can a sample prove commercial suitability?**
A sample can screen taste and process fit, but approval also requires the current specification, representative COA, release method, supply terms, and change-control expectations.
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