Graham writes, “Hello Malt readers!

It’s rare that a topic comes up that is more perfect for a Malt article than the one that follows. I’ve enjoyed being part of this experiment and, in times gone by, would have laboured over this article for an enjoyable few hours. Real work remains dreadfully busy, and any writing right now puts me at serious risk of cognitive overload. Fortunately, the author of the experiment, Kenton, has offered to capture this all for posterity and in doing so, I’m pleased we have another voice for you on Malt. Over to you, Kenton.”

TL;DR for those that want to skip all this waffle and find an important public service announcement within: it’s “crystal clear” you should scroll down to where those two words appear below.

Oh, the pandemic! Home alone in Covent Garden with just myself for company, I quickly realised I’d never want to see another sourdough starter again. I found myself back to basics, trying to find things to ground me… and somehow I found whisky.

Don’t get me wrong: I thought I knew whisky. Well, after a fashion. Thirty years ago, in my mid-twenties, I discovered Laphroaig, back when it was the monstrously fierce peat bomb it cosplays as today. I drank no other whisky for almost two decades. I didn’t like whisky, but I liked Laphroaig. It practically became part of my identity: whisky is grim, except for Laphroaig.

Until one day I tried an Ardbeg… and wow, that was pretty great too. Then in 2012 I found myself in New York’s West Village with some friends who wanted to explore different whiskies. We went to a whisky bar that sold us an “Islay flight” (whatever that was) including both of the aforementioned, plus a Caol Ila and a Kilchoman. What a revelation: all of them were excellent. This was enough to convince me that other whiskies didn’t just exist, but that they could be pretty fantastic, too.

For the next eight years, I started exploring whiskies: three Islay trips, a Speyside trip in an attempt to convince myself it wasn’t gopping, and west coast adventures at the usual suspects on Mull, Skye, and in Campbeltown demonstrated to me that there was far more to this whisky malarkey than I’d allowed myself to experience so far.

And then the pandemic. And nothing much to do other than work up my step count. The devil makes work for idle feet. I walked to the only Whisky Exchange that was open at the time in London Bridge, then I returned via Southwark Bridge and realised that I was near this place I’d heard of called the Scotch Malt Whisky Society.

I gingerly rang the doorbell, was welcomed inside, and my mind was blown. Whisky after whisky, so different, so delicious, revelatory, fantastic. It completely changed my mindset towards whisky. I even warmed to Speysiders. Soon after, I joined a whisky club, and my horizons were broadened even more rapidly than my savings were decimated with the hundreds of bottles I was soon to accrue.

One of the whisky club’s primary oeuvres was for members to buy a bottle of whisky, split it into sample bottles, and send it out to participants at cost price. It’s a fantastic way to try a lot of different whiskies that you might not otherwise try: a sample from a bottle that, once lockdown returned, you couldn’t even try in a whisky bar if you wanted to, at a fraction of the price you’d pay if you could. If you liked it then you could go buy a full bottle for yourself. I soon joined in with this jolly wheeze, splitting and sending bottles across the country. It made sense to split multiple bottles, send out the samples, and join together to sample them over Zoom.

But pretty soon it became clear that glass bottles would easily smash in transit, and they required enormous amounts of packaging to protect them from this, a vast amount of tremendously wasteful non-recyclable detritus just to get the whiskies to their destination without shattering. What about sending in plastic? A bit of research suggested that HDPE plastic – the frosty opaque type of plastic commonly used by distilleries in their thousand-litre IBCs to store whisky – should be inert and not affect the quality of the whisky over time. Flat bottles could be shipped without protection in cardboard sleeves that could be sent at the then-much-cheaper Royal Mail Large Letter rate, and would easily fit through letterboxes, reducing the risk of having to go pick up a parcel at your often not-so-local delivery office.

I sent almost two thousand samples in HDPE over the next year, becoming a cheerleader for this method of shipping. It was easier to package and ship, and the bottles were much cheaper than glass; many others followed my lead. Oh, how I rue that decision today.

Fast forward almost three years. I’ve since co-founded another whisky club with hundreds of members that continues to thrive after most of us handed over the reins to other volunteers. A cornerstone of the new club was once again to encourage others to share whisky samples by mail at cost price. Of course, many people would ship their samples in HDPE plastic, which had by then become normalised.

Some in the club have repeatedly complained for some time about a ‘taint’ detectable from whisky sent in plastic. I believed this was nonsense, and eventually I decided to do something about it.

I recruited volunteers to participate in a blind tasting of the same whisky that had been stored in plastic bottles or glass bottles for two months. The source bottle was a single-cask eight year old Ben Nevis matured in a first-fill ex-bourbon hogshead and bottled at 59.8% ABV (SMWS 78.51). There were seven samples distributed to participants. The participants didn’t know how many of the samples had spent the two months in plastic bottles or in glass bottles. Their sole job was to detect those that had been stored in plastic or in glass. There would be a £50 prize for anyone that got closest to the correct answer. I didn’t tell any of the participants anything more than this. I quickly found the “dirty dozen” to participate, including some of the most vocal anti-plastics, and the game was on.

To the samples: I had a hunch that when people complained about plastic, they were actually detecting contact with the plasticised cardboard insert in the bottle lid. So, I picked three samples: 50ml HDPE plastic, 30ml HDPE plastic, and 50ml glass. Within each type, each was stored either vertically with no lid contact, or horizontally with the whisky touching the lid, making six samples in all. Each of the six aforementioned samples totaled 100ml, so for 50ml bottles there were two identical bottles, and for 30ml there were three (they can actually store about 36ml). The seventh sample was the remainder of the bottle, stored in its original bottle, albeit with about 85% air contact.

Got that? Good. Remember, I believed HDPE plastic was inert and would not affect the taste. That’s why I did lid contact versions too.

Two months later, I bottled seven samples into 7ml glass sample bottles and distributed them to each of the twelve participants. They all had unique bottle codes so that they couldn’t confer. I awaited people to submit their findings. One of them couldn’t participate in time, so I received eleven results.

Let’s do a bit of maths: if you toss a coin, what’s the chance of you guessing at random whether it’s heads (plastic) or tails (glass)? One in two, right? Getting it right twice in a row, one in four. Seven times in a row, two to the power of seven, or one in 128.

Four of the eleven detected everything correctly. A fifth almost got it right; he said one was a bit dodgy, if he’d said plastic rather than glass then he would have 100% too. A sixth said that just two were plastic. When I told him there were two more to find, he found them.

I left maths behind almost four decades ago, but statisticians amongst you can work out the chances at random of four (or five, or six) from eleven getting that 1-in-128 right. Someone update me in the comments and I’ll put it in here, but I reckon we’re close to billions-to-one.

Once the plastic-or-glass findings were submitted, it was revealed to participants that some of the samples were stored vertically with no lid contact, and some horizontally with lid contact. One of the participants then further identified the 30ml bottles as more tainted than the 50ml bottles, and even that the horizontal 50/30 were more tainted than the vertical 50/30. Even before he knew the bottle sizes, or even that there were four plastics to find. He was also the only one to detect the original sample as the tiebreaker, and won the token prize money we all contributed to as part of the game. Some other participants, when prompted, detected something about the lids, but it didn’t seem to be a hugely significant factor: by far the biggest determinant of contamination was whether they’d been stored in HDPE or in glass.

It seems conclusive from this experiment that two months in HDPE plastic can affect the taste of whisky. It’s crystal clear that you should not store your whisky in small HDPE sample bottles for any significant amount of time.

I would like to publicly apologise to those that I rubbished for their belief that HDPE plastic affects whisky samples over time. It clearly can have a significant impact – even I managed to detect most of them too. If nothing else comes from our cod-science research, let’s ensure that we drink or decant our plasticised whisky as soon as we receive it.

But further research is required, and with a bit more scientific rigour now that it’s certain there can be a discernible effect. The most troublesome question is whether HDPE affects samples during transit: the few days that whisky will inevitably spend between bottling, shipping, and consumption or decanting into glass. I will be inviting the top performers above to a further experiment where we store in HDPE for four days horizontally, mimicking the life cycle of a sample sent through the mail, to see whether the change is still detectable in a much shorter period of time. The results will be published here in due course.

It was fun to do a whisky Zoom again to debrief and discuss our findings. Stockholm Syndrome has clearly kicked in to make me pine for the days when there were no tourists around, everything in the West End was closed, and all we had was our whisky mates for company, sending samples through the mail and enjoying them together on video. But if it ever happens again, next time I’ll definitely be cheerleading for glass.


Kenton is based in London and is a big fan of single malt Scotch
whisky, with a preference towards bold and dirty flavours, bonkers
cask influences, and Islay peat monsters. Having over a hundred open
bottles sprawled throughout his home, he's trying to bottle-kill a
bunch of those before refilling the much bigger FOMO-driven whisky
loch that got a bit out of hand during the pandemic - a time when he
also co-founded Capital Whisky Club, which raised over £80,000 for
good causes in its first two years.

  1. Niels Viveen says:

    Hi Matt, the bottles you show in the image do not seem to be food safe, alcohol proof plastic.
    You need to get a special type of HDPE that is food and alcohol/oil safe.
    I use a clear type HDPE food safe bottle and never had any complaints.

  2. MaxHill says:

    It seems unnecessary to me due to lack of knowledge. Did anyone actually bothered to read information on plastic bottles either with water or official miniatures with alcohol? You would find 1 in triangle or even PET. Please next time use PET and you could leave your samples for years in those. Plain polyethylene with whatever density or polycarbonate or acrylate is not OK, only polyethyleneterephthalate – industry has already done all those tests decades ago.

  3. Genevieve says:

    Sounds like an interesting experiment! I don’t know enough about it myself, but even if, as others have commented, the type of plastic used could be the issue, this is something worth keeping in mind (and asking about) when purchasing sample flights or things like whisky advent calendars from different shops.

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