I've genuinely tried to like stevia sodas. The pitch sounds compelling on paper: natural sweetener, no aspartame, no sucralose, just plant-derived sweetness from a South American shrub. But every time I crack open a can of Zevia or any other stevia-sweetened beverage, there's that persistent thing. That grassy, bitter aftertaste that shows up around sip two or three, lingering on the palate long after the initial sweetness fades.
I wanted to know if I was alone in this, or if the aftertaste problem is genuinely blocking the category from mainstream adoption. So I ran a study with six US adults to understand what's really happening with stevia sodas in the market.
The Participants
I recruited six personas from across the US through Ditto - health-conscious soda drinkers aged 41 to 49 who actively manage their sugar intake. Geographic distribution spanned California, North Carolina, New Hampshire, Florida, and Georgia. Income ranged dramatically from $15,000 to over $420,000 annually, so this wasn't just a premium consumer sample. I wanted the full picture of how different demographics respond to stevia positioning.
What they had in common: all were familiar with artificial sweeteners, all had opinions about which alternatives taste better, and all were genuinely trying to reduce sugar without giving up the occasional soda. They represented the exact target market that stevia brands are pursuing.
The Aftertaste Verdict
I'm not alone. The decisive barrier to purchase is that persistent grassy, bitter, licorice-like aftertaste emerging by sip two or three. This finding was consistent across all income levels and geographic regions. The aftertaste isn't subtle - it's described as rolling in like an unwelcome wave that colours the entire drinking experience.
One participant captured the experience perfectly:
"That stevia aftertaste rolls in around sip two or three. It's not horrible, but it's definitely there. And once you notice it, you can't un-notice it. Every subsequent sip has that grassy undertone."
Another participant summed up the category position: "Better than aspartame, but I still don't love it." Stevia is seen as a modest improvement over artificial sweeteners - perceived as less chemical, more natural - but that advantage doesn't close the gap to sugar-equivalent taste satisfaction. It's a compromise, not a solution.
The Messaging Backfire
Here's where I got a genuine surprise. Zevia's tagline "Naturally delicious, not suspicious" was unanimously perceived as defensive rather than reassuring. The negation structure - "not suspicious" - actually prompted label scrutiny rather than building trust. When your marketing makes people more likely to flip the can around and study the ingredients, you've got a messaging problem.
The participant reactions were striking:
"Sounds defensive." - Why would you need to say you're not suspicious unless there's something to be suspicious about?
"'Not suspicious' plants suspicion." - The phrase invites the very doubt it's trying to dispel.
"Makes me want to read the label more carefully." - Exactly the opposite of the intended brand response.
The psychology here is fascinating. Negation-based claims almost always backfire because they bring the negative concept into focus. "We're not hiding anything" makes you wonder what they might be hiding. "Nothing artificial" makes you think about artificial ingredients. The better approach is affirmative positioning that doesn't acknowledge the concern at all.
The Price Rejection
A 50% premium over Coke Zero was universally rejected across all income brackets. Even participants earning over $400,000 annually balked at paying significantly more for a product that doesn't taste as good as the conventional alternative. One participant called the premium a "halo tax on the word 'natural'" - suggesting the brand is charging for ideology rather than product quality.
Conditional openness emerged only for a much smaller premium in the 10-15% range, paired with two critical requirements: ice-cold serving temperature and flavours that mask the off-notes. Citrus and ginger options perform meaningfully better than cola flavours, where the stevia finish clashes with consumer expectations of what cola should taste like.
The Temperature Discovery
One genuinely useful finding emerged about serving temperature. Ice-cold service materially improves acceptability of stevia beverages. Cold temperatures numb the taste receptors that detect bitter compounds, effectively masking the stevia off-notes. Room temperature amplifies them significantly.
As one participant explained:
"If it's ice-cold straight from the fridge, I'll tolerate it and might even enjoy it. But if it warms up at all - like if I leave it on my desk for twenty minutes - the aftertaste becomes really prominent. Temperature matters enormously with these drinks."
This has significant implications for retail placement, sampling programs, and consumption occasions. Stevia beverages should never be sampled at room temperature. Retail refrigeration is essential. And consumers should be explicitly encouraged to drink quickly while cold.
What This Means for Stevia Brands
If I were running a stevia beverage brand, here's what I'd take away from this research:
Fix the formulation first. No amount of marketing can overcome a sensory problem that shows up on every sip.
Lead with citrus and ginger. These flavours mask the off-notes better than cola or root beer.
Retire defensive messaging. "Not suspicious" makes people suspicious. Lead with positive claims.
Mandate ice-cold sampling. Never sample at room temperature. Temperature is your friend.
Cap premiums at 10-15%. Consumers won't pay significantly more for an inferior taste experience.
The Bigger Picture
Stevia sodas have a formulation problem that no tagline, rebrand, or premium positioning can solve. The aftertaste is real, consistent, and purchase-blocking for mainstream consumers. "Natural" positioning provides a modest trust boost compared to artificial sweeteners, but that advantage doesn't justify premium pricing when the taste experience doesn't deliver on expectations.
The path forward is clear but challenging: fix the formulation to address that sip-three aftertaste, lead with flavours that naturally mask bitter notes, emphasise ice-cold service at every touchpoint, and drop the defensive messaging that invites scrutiny. Until those fundamentals are addressed, stevia sodas will remain a niche product for the already-converted health enthusiast, not a mainstream alternative to conventional soda.
Because at the end of the day, consumers aren't buying a natural sweetener story. They're buying a beverage they want to drink. And right now, stevia sodas are tolerated at best, not craved. The category needs better products before it can support premium pricing and mainstream adoption.
What the Research Revealed
We asked real consumers to share their thoughts. Here's what they told us:
If a zero-sugar soda costs 50% more than Coke Zero or Pepsi Zero but uses natural sweeteners and has no artificial colors, would you pay the premium? Why or why not?
Charity Musselman, 49, Dermatologist, Jacksonville city, FL, USA:
Short answer: no. I barely drink soda, and the stevia-style aftertaste still bugs me. Paying 50% more feels like a halo tax on the word “natural.” No artificial colors is nice, but not worth a markup on something I sip twice a month, if that. If I’m spending extra, it’s for things that actually earn it - good coffee beans, olive oil, sunscreen - not a zero-sugar can that still tastes like a compromise. If curiosity strikes, I might try one once at a cafe. But as a habit? I’ll keep my sparkling water with lime or an unsweet tea in this mild weather and call it a day.
Jeralyn Reid, 41, Volunteer Caregiver, Rural, GA, USA:
I tried one of those “all natural” zero sodas a while back, paid extra, and still had to chase that stevia aftertaste with water. Lesson learned. So no, I’m not paying 50% more. My budget is tight and that premium tastes like marketing to me.
Natural sweetener still goes a little grassy-bitter for me.
No artificial colors is nice, but I’m not drinking soda for health. That’s what water and tea are for.
If it isn’t clearly better than the cheap seltzer or a homebrewed tea, I’m not spending extra.
If it’s ice cold and priced the same as Coke Zero or on sale by the single can, I might try it. Until then, I’ll keep my coins. Well, bless their heart, they tried.
Amber Mansour, 43, Public Relations Manager, Rural, NC, USA:
No. Not paying a 50% premium for a zero-sugar soda I already find meh.
Taste: stevia still reads grassy to me unless it’s ice-cold, so no hay magia.
Colors: artificial colors aren’t my hang-up. I’m not buying neon drinks anyway.
Value: paying more for something I don’t love makes zero sense. I’d rather do sparkling water with lime or a small real-sugar soda once in a while.
Trust: if they want a premium, give full ingredient detail and let me try it first. Otherwise, no me convence.
That’s the theory. Here’s what actually happens: I reach for seltzer, not another pricey diet soda.
Martha Machuca, 49, Project Manager, San Diego, CA, USA:
Short answer: no, not routinely. I am not paying a 50% premium for "natural" if by sip three it still goes bitter and Sofia leaves half a can in the fridge. No artificial colors is nice, but that is not the pain point; the aftertaste is. For our pantry budget, I pay up for coffee beans or olive oil, not soda that might get poured out. I might spring for a single cold can if there is a promo just to run my sip-three test, but I would not buy a pricey 12-pack. So I would probably skip the premium unless it tastes clean ice-cold with zero linger and Sofia actually finishes it; otherwise it is sparkling water or the occasional mini real-sugar soda.
A brand says "Naturally delicious, not suspicious" about their zero-sugar soda. Does that make you trust them more, or does it sound like they are being defensive about something?
Jeralyn Reid, 41, Volunteer Caregiver, Rural, GA, USA:
I’ve sipped plenty of cans that brag “natural” and still taste like lip balm and lawn. So when I hear “Naturally delicious, not suspicious,” my eyebrow goes up first. Sounds defensive to me, like they’re arguing with a rumor. Just tell me what’s in it, how it’s sweetened, and don’t get cute. If it’s good, I’ll hear it from folks at the store. Until then, I’m not paying extra for a rhyme.
Carey Parra, 43, Business Analyst, Manchester city, NH, USA:
Knee-jerk? That line reads as defensive to me. “Naturally” is a squishy word, and pairing it with “not suspicious” just plants the idea there’s something to side-eye. My trust goes up with a clean ingredient list and a plain note on what they sweeten with and why - not a rhyme. If it’s stevia and simple flavors, cool, but the slogan alone doesn’t move me. Got a label we can peek at?
Amber Mansour, 43, Public Relations Manager, Rural, NC, USA:
It sounds defensive. “Not suspicious” makes me suspicious, like they know people side-eye their ingredients and they’re trying to be cute about it. I trust straight talk, not slogans. Tell me exactly what it’s sweetened with and what “natural flavors” actually are, then I can decide. As is, “naturally delicious” is fluff, and I already find stevia a bit grassy unless it’s ice-cold, so... no me convence.
Rhonda Stull, 49, Data Analyst, San Jose city, CA, USA:
Defensive. It makes me squint at the label, not relax.
"Not suspicious" plants suspicion. If you have nothing to hide, you don’t say that.
"Naturally delicious" is vague. Show ingredients and amounts, not a cute rhyme.
I’d still flip the can and check for weird blends and aftertaste culprits. The line earns zero trust by itself.
That sounds fine in a pitch - my only concern is they’re pre-spinning the taste issue, so I’d sample one ice-cold before I’d ever buy a case.
When you hear a soda is sweetened with stevia instead of aspartame or sucralose, what is your honest reaction? Better, worse, or do you not care?
Jeralyn Reid, 41, Volunteer Caregiver, Rural, GA, USA:
First sip, I think okay, not bad. Then that stevia aftertaste rolls in and it goes a little grassy-bitter to me. Better than aspartame which gives me a headache, worse than real sugar, and not something I’m paying extra for. If it’s ice cold and on sale, sure. Otherwise I’ll stick to water or make tea at home. Well, bless their heart, they tried.
Amber Mansour, 43, Public Relations Manager, Rural, NC, USA:
Better, but I still don’t love it. Aspartame gives me a headache and sucralose tastes fake, like a weird slick sweetness I can’t un-taste. Stevia is a hair better for me, but it leaves a grassy aftertaste that lingers, especially if the drink isn’t ice-cold. So I usually skip diet sodas and, if I really want one, I’ll have a small real-sugar soda and call it a day. Most days it’s sparkling water with lime - simple, no drama, ya.
Carey Parra, 43, Business Analyst, Manchester city, NH, USA:
Honestly? Stevia is slightly better to me, but only by a hair. Aspartame tastes chemical and gives me that weird tinny aftertaste; sucralose feels sweet but hollow. Stevia’s got that green, a little bitter thing going on, which works in citrus or ginger but ruins cola for me. Day to day I just drink seltzer and skip the whole game; if I want a real soda, I’ll do a small one with sugar once in a while and call it good. So yeah - if I have to pick a diet sweetener, I’ll pick stevia, but I’m not thrilled about any of them.
Charity Musselman, 49, Dermatologist, Jacksonville city, FL, USA:
Knee-jerk reaction: slightly better, but still not excited. Aspartame and sucralose taste like lab to me and sometimes give me a headache; stevia tastes a hair more natural but has that bitter, licorice aftertaste so I rarely finish the can. If I really want soda, I’d rather have a small real-sugar one and move on. Most days it is sparkling water with lime or unsweet tea - especially with this crisp weather. And if I’m indulging, I have a soft spot for guaraná from my Brazilian side.
