SCIENCE! Glass Vs. Plastic Vs. Aluminum

The Pooj goes all in.

For our latest installment of SCIENCE! we foray into the age old question of whether delivery system (i.e. bottling method) affects the taste of what it’s delivering. A&W Root Beer is sold in many different vessels – glass, PETE (plastic, that is, not some guy named Pete schlepping a barrel around…), and aluminum. For the purposes of this experiment, we used a 12 oz. glass bottle, a 20 oz. plastic bottle, and a 12 oz. aluminum can. Despite the differences in delivery system, the formulas for each root beer remain exactly the same according to the ingredient lists.

Il buono, il brutto, il cattivo. (From L to R: glass, aluminum, and plastic.)

I can’t vouch for the flavor differential of the 1- and 2-liter plastic bottles (or whether they are PETE as well, or even if they are the same formula, for that matter), but our test subjects (the missus and myself) can certainly taste a difference in the vessels we used.

First off, we drank directly from the delivery vessels. Both subjects agreed that the root beer out of the glass bottle was blander than what came from the other two containers – Subject 1 went as far as to call it “fizzy water.” Both subjects also agreed that the plastic bottle added some strange aftertaste to the root beer – sour in Subject 1’s case and salty and chemically in Subject 2's case. Subject 2 also noticed a difference in carbonation levels – the glass bottle sample seemed to have the least volume of carbonation, but bigger bubbles, while the plastic bottle felt like it had more, but smaller, bubbles. The can’s carbonation felt the hardest, almost burning in comparison.

For the second test, subjects drank the root beer out of identically sized and composed glasses. Subjects were told which bottle was poured into each glass before drinking from it to see if they could taste a difference between the direct sip (i.e., out of the bottle/can) versus the poured sip. You can actually see the difference in the carbonation on the photo. The glass bottle root beer does in fact have visibly bigger bubbles and the least head, while the plastic bottle variety has little to no visible bubbles aside from the foamier head. For all its carbonation, the canned version shows relatively small bubbles, which gather at the top of the glass, but are a little too big to be considered foam – most of the head dissipated soon after the pour.

Safety first.

Out of the glass, Subject 1 thought the glass-bottled and plastic-bottled versions tasted more similar, or at least similarly sour. Subject 2 actually thought the 3 versions didn’t taste that different, although the canned root beer still seemed to have the hardest carbonation.

Thus we move onto our third and final test: the blind taste test. Subjects were given 3 glasses, each containing one of the root beer varieties, and were tasked with identifying which beverage came from which vessel based on taste alone. This, of course, was based on their previous impressions of each beverage, depending on the delivery system.

The “empirical” data, for interested parties.

Subject 1 did not identify any beverages correctly, although picked the glass-bottled root beer to be the sourest thinking it to be the plastic-bottled variety. This is somewhat consistent with their earlier impression that the glass- and plastic-bottled versions tasted more similar when sipped from a glass. Subject 2 identified the glass-bottled root beer correctly based on the relative blandness and carbonation. However, Subject 2 mixed up the plastic and aluminum samples, noting a more chemically aftertaste in the aluminum sample and a harder carbonation in the plastic sample.

While the subjects could not exactly identify which root beers were which (honestly, after drinking each of them so many times for the sake of the experiment, they started to taste the same…), there was a conclusive difference in flavor depending on the delivery vessel. There was also a general agreement that the processed flavors of the can and plastic bottle tended to alter the taste of the root beer – glass bottles seem to preserve flavor the best (which might be better if there was more flavor in the root beer to begin with – see my previous A&W post…).

There was also general agreement that we drank way too much root beer and ingested way too much carbonation for one evening…

Remember to tip your bartender/lab partner.