Great Canadian Diet Soda Test

I don’t smoke, I don’t do drugs, and I hardly ever drink. In most circles, this is what would qualify me as “boring nerd-boy”. My vice of choice for years has been Diet Coke. In those same circles, this would be known as “Seriously? That’s a vice to you? Nerd.” I would then sheepishly slink away muttering something about my mom thinking that I’m cool.

In high school I drank what I will scientifically call a ‘butt-load’ of the stuff (4 litres a day!), and I could swear that it was my favourite of all sodas (or “pops” as we call them in Canada….don’t we?). When I was cutting down my coffee intake, Diet Coke was there to fill the gap. When I broke my hip and came out of surgery, I wanted nothing more than to drink a cool can of Diet Coke.

In short, I was (am?) lame.

But I’ve never been put to the test. When asked at a restaurant if Diet Pepsi was an acceptable alternative to Diet Coke, I would answer “yes”, (mostly to not be a jerk-wad), but what do my taste buds really think about this? Am I so blind to brand loyalty? I needed to find this out, so the Missus (a long-time Diet Pepsi drinker) and I set out to perform a double-blinded study to determine what we truly liked best. Diet Coke or Diet Pepsi: Who will reign supreme?

Whose food-stuff will be the good-stuff?

The Method

We used 8 different brands of cola. The main competitors were Diet Coke and Diet Pepsi, but we also wanted to include several non-brand diet colas too: Colt, Selection, Our Compliments, and President’s Choice filled out the low-cost variety (since these brands are unique to a given grocery store chain, we went to all the ones in my area for their house-brand), and just for good measure, we also included regular Coca Cola Classic and Pepsi.

Pictured: The contenders in front of a totally not-staged skeptic-friendly bookshelf

We each predicted what we would like best. My predictions for taste preference were, in order 1) Diet Coke, 2) Our Compliments, 3) Colt 4) President’s Choice 5) Diet Pepsi 6) Selection 7) Pepsi 8 ) Coca-Cola.  I used to work in a grocery store that sold Our Compliments, so I figured it would place pretty high (since I drank it often there), while straight cola has grossed me out for years, which is why I placed them at the bottom.

We had two sets of 8 drinks, kept in different rooms so that tasting could be done alone (i.e., blinded from each other). Using an 8-sided dice, one taster assigned a pop to be poured into a given cup, labeled from 1 to 8, for the other taster. The pop assignment key was kept by the person who did the assigning, not the person tasting. The pop was at room temperature (so as not to shock our taste buds with coldness). We switched rooms and began our taste test.

The Testing

We had two things to list based on taste: What brands we were drinking, and what we liked best. We cleansed our palates with regular gulps of water while we set about our drinking 8 cups of warm soda.

Pictured: “Yum”

It was terrible. Imagine it: eight bloody cups of warm black goo. When pop is warm, the carbonation fades quickly, so we didn’t even have that much in the way of bubbly stinging to dull the grossness of drinking several cans worth of pop inside of a few minutes. It was like drinking the blood out of most of the Nine Riders and having to rank them from worst to least-worst.

From left to right: President’s Choice, Pepsi, Diet Coke, Coca….awww, to hell with it. It was all bad.

Some of the drinks had a flavour that stood out like a sore thumb (or more accurately, like a gross pop). It was easiest to taste the gross ones, and rank them near the bottom first, then work up to the tastiest. One drink in particular made me yelp out “Ah, my God, that’s awful!” I thought it was Coca Cola Classic (I’ve long hated that taste), and immediately ranked it at the bottom. As I moved up the list, the last two were particularly difficult to distinguish from each other, let alone pick a favourite. By that time, I had drank nearly 2 litres of diet and regular soda in about 8 minutes, and I was exhausted, feeling gross, and incredibly burp-ey. I just wanted to pick one, and get out of that bile-filled room so that I could eat a slice of cold pizza that was waiting as my reward for a job gross-done.

The Results
My actual taste preferences were as follows:
  1. Our Compliments
  2. Diet Coke
  3. Selection
  4. Colt
  5. President’s Choice
  6. Pepsi
  7. Coca-Cola Classic
  8. Diet Pepsi
So it looks as though I have taken a few valuable lessons from this testing:

  1. I do indeed like Diet Coke quite a bit.
  2. I like Our Compliments even more, but just by a small amount (because of my difficulty in picking a preference).
  3. My predictions weren’t that far off.
  4. When next time a waiter/waitress asks me if Diet Pepsi is okay, I’ll have to say, “EWWW! For God’s sake, are you trying to make me vomit? I’ll take a Root Beer!”
The Missus’ results were a little more across the board, but there were a few things for her worth noting:
  1. She likes Diet Coke more than Diet Pepsi after all.
  2. She likes the cheapest diet cola the most (“Selection” from the Food Basics chain).
  3. We both think very little of regular colas.
The Future?

After such a long testing, a few problems/limitations became evident:

  1. Drinking the pops warm is not necessarily an accurate reflection of their taste because they are meant to be served chilled, so a cold-test should be in order.
  2. Water was a poor palate-cleanser. Crackers or bread would have been better.

That last point is especially important. When we were done our testing, but before we compared our results, we both hung around in a third room (my kitchen) as we ate our cold pizza. I have a very small kitchen, there is no place to sit down, and we never hang out there….it was almost as though we were hiding from the pop. We both felt full of black goo… And yes, it feels exactly like you are imagining it to feel like.

About an hour later, we were both incredibly hyper. Her legs were all twitchy, and I was literally bouncing up and down. The caffeine levels in the various pops hovers between 36 mg/can and 46 mg/can, so we can split the difference, and assume that the average caffeine content of each can was 41 mg. As we both drank about half a can of each of our 8 pops, that’s approx 164 mg (or: [41 ÷ 2] x 8 = 164…I don’t do math often so I hope I wrote that correctly) of caffeine consumed in 10 minutes. That’s more than two FULL cans of Red Bull! Only hard-to-get-along-with-teenagers should be doing this. Not adults.

I do NOT recommend people do this the same way we did. Eight cans was needless, as it made choosing a favourite too hard, and the caffeine intake alone was approaching dangerous levels. It was also so gross that neither one of us even wanted to continue drinking, let alone make a thoughtful decision about the Nazgul-blood we were forcing down our gullets.

So while I can say with certainty that I do indeed like Diet Coke a lot, I cannot be certain that I like Our Compliments the most, because the test was with warm drinks, and there was a level of fatigue experienced by the tasters (the Missus and me). Next time, we’ll reduce our sample size to just four, serve them cold, and use bread/crackers as a palate cleanser.

In the meantime, no. Diet Pepsi is NOT okay. Get that black dog-snot away from me!

14 Responses to “Great Canadian Diet Soda Test”

  1. Jeremy Banks says:

    I've been meaning to do some double-blind taste tests. Perhaps this will inspire me to actually do so.

    > That's more than two FULL cans of Red Bull!

    While this is true it seems a little misleading since caffeine is only one of several stimulants in Red Bull, n'est pas?

  2. Eamon Knight says:

    Using an 8-sided dice

    The mere fact that you own one or more of these tells us how much of a nerd you are ;-) .

    (Full disclosure: yes, we also have a set or three of polyhedral dice lying around somewhere).

  3. Steve Thoms says:

    Jeremy, that's true that Red Bull is loaded with other stimulants, but I chose Red Bull for a few reasons

    1) An 8 oz can contains 80 mg of caffeine
    2) I would have gone with "x cups of coffee", but most people drink very different sizes of coffee, so I was concerned about the maddening subjectivity of coffee. Also, Depending on how you prep the coffee, the caffeine content is affected….at least Red Bull is consistent.
    3) The narrative: Red Bull is widely recognized as the "Why is this legal?" drink marketed to to kids because of how hyper it makes them, and I hadn't felt that jumpy in years.
    4) Drinking that much diet cola is terribly gross. Drinking any amount of Red Bull is too. I also wanted to take a stab at Red Bull for having a drink that a) gets you more hyper than should be allowed without a doctor's prescription, b) tastes like liquefied skittles and sweat.

    Eamon: Actually, I used an 8-sided dice roller online. The fact that I know where to find one is no consolation. And in full disclosure as well, I DO have a full set of nerd-dice, but I just wasn't able to find it that day :)

  4. xinit says:

    Not exactly double-blind if you have working taste buds – I haven't tried all of the above drinks, but I know the difference between Diet Coke and Diet Pepsi. Sweetness and carbonation levels are surprisingly different without getting into flavour.

  5. cynthb says:

    It'd be interesting to do a comparison between cans, plastic bottles, and fountain drinks (syrup + water).

    I also like diet coke significantly more than either diet pepsi or PC diet cola, but I've never done a blind test.

  6. Laura Shea-Clark says:

    At least he didn't write a random number generator program in Fortran! ;-)

    Some of the these diet colas have an aromatic hydrocarbon taste (reminds me of chloroform) that I find rather distateful. At least Diet Coke in the can doesn't seem to feature this.

  7. Jo says:

    Pretty fantastic! Well done! Though I have to say that Red Bull is the only reason I get through exam season… we're BFFs! I appreciate the kick it gives me when I need it — I don't think it's meant to be enjoyed as a pop, but as an alternative to a kick in the pants to wake up.

    I enjoyed reading and hope you'll do your second sometime when you don't feel like puking! :D

  8. Parrot says:

    Here's an interesting experiment:

    Get some Diet Coke and Diet Pepsi, pour three glasses (two of one, one of the other), then have a sip of each one and instead of trying to guess which is which, just try and figure out which one is different.

    It's a little harder than you'd expect.

  9. Steve Thoms says:

    @Parrot: Well, I'm pretty sure I would get that one right, judging by my way-grossed out gagging (and drama-queen yelling in disgust) that I did when I tasted the Diet Pepsi…

    The last three (also my top three) drinks were very hard to tell apart, and the last two took a lot longer (Diet Coke and Our Compliments).

    Another note of interest: when pouring the pops into the various cups, different ones bubbled in VERY different manners, so it's extra-important to let the drinks settle for a few minutes before diving in.

  10. PharmacistScott says:

    In addition to the limitations you noted above, I'd be interested to see how reproducible your selections are: would you pick the same products, in the same order again? The degree of correlation will give us an idea of the real differences between the products.

  11. Kimberly Hebert says:

    I suggest the ol' taste and spit for next time.

  12. Nickname unavailable says:

    Coke zero has been a favorite of mine, but it can be hard to find. One day I'll have to go crazy and do a taste test to see if it REALLY is my favorite.

  13. Jack says:

    ah you’re full of aspartame, that explains so much. I actually feel a little sorry for you now

    • Steve Thoms says:

      Ah, so it took you this long to discover that we have a whole website here, and there are many posts. That explains so much. I actually feel a little sorry for you now.


  • Steve Thoms

    Steve is a professional music teacher living in Kitchener, Ontario. He studied recorded music production at Fanshawe College, and Political Studies/History at Trent University, where he specialized in political economy and global politics. He is an amateur astronomer, and an award-winning astro-photographer. Steve also runs the blog, Oot and Aboot with Some Canadian Skeptic." can can be followed on Twitter, @SomeCndnSkeptic.