Thirty issues. It feels good to be back writing these regularly again. Fittingly, this issue number matches the age of my birthday dram from last week. Every year on my birthday, I pour a glass of my Benromach 30 Year Old, a gift from my wife and in-laws when I turned 30 five years ago. Thirty years in a cask, thirty issues in your inbox; only one of those required real patience

This one is about the fine print: the words on labels, dials, and window stickers that everybody reads and almost nobody questions. "Sour mash." "17 jewels." "40 mpg." Each one is technically true. Each one is hiding a much better story. It’s a shorter one, but one that’s been on my mind. Especially the last one. Let's go get them.

Pick up a bottle of Jack Daniel's and you'll see "Sour Mash" printed on the label like a tasting note. It isn't one. Sour mash is a process, and it happens before the yeast ever gets to work. When a distillation run finishes, the still leaves behind hot, acidic, protein-rich spent liquid called stillage. In a sour mash distillery, a portion of that liquid, known as backset (or setback), goes into the next batch of cooked grain. Whiskey made with backset is sour mash; whiskey made without it is sweet mash [1]. That's the entire distinction, and it's why the phrase on a label tells you less than the marketing department hopes. The overwhelming majority of American whiskey is made this way, and sweet mash is mostly the domain of small distilleries [13].

The point of all this is pH control. Backset carries lactic and acetic acid from the previous fermentation, and lowering the mash's pH makes it a hostile neighborhood for stray bacteria that would otherwise compete with the yeast for sugar. Greg Metze, the former master distiller at MGP and Old Elk, has described backset as the preferred souring method largely because the acid comes free, with a target of roughly pH 4.8 to 5.0 [1]. At Jack Daniel's, about 30% of each batch is backset, which drops the mash from around pH 5.6 to 5.3; the distillery separately sours its yeast starter with lactobacillus to bring it to about 5.0 [2]. That second step, the lactic soured yeast mash, is the older and less famous half of the tradition [4]. Industry figures put backset anywhere from 10 to 30% of mash volume, and the benefits go beyond acidity: spent yeast in the stillage feeds the next generation, and the distillery reclaims heat and water it would otherwise dump [3]. If you've ever babysat a cell culture, this is familiar. You buffer the media, you feed the cells, and you make the environment unfriendly to anything you didn't invite. Sour mashing is essentially 19th-century media prep.

The man usually credited with it is Dr. James C. Crow, born in Inverness in 1779 and trained in medicine and chemistry at Edinburgh, who ended up distilling for Oscar Pepper near Versailles, Kentucky, on the site that is now Woodford Reserve [5]. Crow brought lab habits to a farm craft: litmus paper to check mash acidity, a saccharimeter for sugar, thermometers and hydrometers for everything else [5]. The honest version of the story is that he didn't invent sour mashing; he understood it and tracked pH, specific gravity, and temperature well enough to make it repeatable [6]. That rigor paid off. Later refinements to backset practice reportedly lifted yields from about 3.5 gallons of whiskey per bushel in Crow's day to 4.2 gallons by the 1890s [7], and his name became Old Crow, which a century later was America's best-selling whiskey and the first bourbon brand to top a million cases a year [8].

Skip the backset and you get sweet mash: fresh grain, fresh water, fresh yeast, every single batch. Wilderness Trail in Danville ferments each batch with fresh yeast alone [9] and has said it was the first distillery since Prohibition to embrace sweet mash as its technique [10]. The catch is the reason sour mash exists in the first place. Without the acid buffer you're relying on sanitation, so co-founder Dr. Pat Heist built the operation around proprietary, ultra-sanitary methods to keep bacteria and wild yeast out [11]. Other distillers choose sweet mash for logistics. Castle & Key runs roughly 25 mash bills a year for itself and contract clients, and found it hard to keep backset consistent when the previous batch was an entirely different recipe [12]. And in a nice bit of irony, Woodford Reserve, sitting on the exact ground where Crow refined sour mash, has experimented with sweet mash itself [14].

Here's the twist for the Scotch side of the bar. Scotch must be fermented only by the addition of yeast [15], so there's no scoop of last week's stillage going into a washback. Every Scotch is, in effect, a sweet mash. The bacteria get in anyway. Scotch worts aren't boiled, so lactic acid bacteria riding in on the malted barley survive into fermentation, bloom once the yeast slows down, push the pH to around 3.8, and drive up ester levels in the new make [16]. A Heriot-Watt doctoral study found these bacteria make up a major part of the natural microflora in Scotch malt fermentations, and some strains boost the compounds behind malt whisky's "sweet and fatty" character [17]. That's why a distillery bragging about long fermentations (anything past about 75 hours counts as long) is really bragging about its bacteria [15].

So Kentucky sours its mash to keep bacteria out, and Scotland leaves the door open to let them in. Both end up with acid shaping what's in your glass. They just disagree about who sent the invitation.

Flip over plenty of quartz watches and you'll find a jewel count printed on the movement or the caseback, which feels like a contradiction. Jewels belong to hand-wound calibers and exhibition casebacks. Why would a battery-powered watch need rubies? Because a quartz watch is really a story about two crystals: one that keeps the time, and one that keeps the watch from grinding itself apart while it does.

Start with the quartz. In the 1880s the Curie brothers showed that certain crystals, quartz included, generate a voltage when squeezed and physically flex when a voltage is applied [18]. Cut quartz into a tiny tuning fork, about a tenth of an inch long, feed it a whisper of current, and it rings at 32,768 vibrations per second [19]. That number isn't arbitrary: it's 2 to the 15th power, so a chip can halve it fifteen times and land on exactly one pulse per second to drive the stepping motor [19]. For perspective, even a high-precision mechanical balance oscillates 8 to 10 times per second [18]. Seiko put it on a wrist first with the Quartz Astron 35SQ on Christmas Day 1969, priced at 450,000 yen, roughly the cost of a popular car at the time; its crystal ran at 8,192 Hz before 32,768 became the industry standard [20]. Seiko then opened its key patents to the world, which is why nearly every quartz watch since runs on its blueprint [18].

Now the ruby. A ruby is corundum, crystalline aluminum oxide, colored red by a trace of chromium [21]. Watchmakers have used jewel bearings since a 1704 English patent by Nicolas Fatio de Duillier and Peter and Jacob Debaufre, originally with natural stones [21]. The game changed with French chemist Auguste Verneuil, who dropped finely ground alumina through an oxyhydrogen flame and let it recrystallize into a carrot-shaped boule; about 5% chromium oxide gives a pale pink stone, 6% a deep red [22]. He filed a sealed note with the French Academy of Sciences in 1886 and announced the process publicly in 1902 [23]. The result is chemically and physically ruby, cheap enough to slice into bearings by the thousand. The jewels in your watch are real rubies in every sense a mineralogist cares about. They just never saw a mine.

So why so few in quartz? Jewels earn their keep where there's load. In a mechanical watch, mainspring torque pushes through the gear train around the clock, and steel pivots spinning in brass holes would wear fast without a hard, polished bearing. In a quartz watch, the stepping motor nudges the hands with so little torque that the bearings see almost no pressure, which is why a large share of quartz movements skip jewels altogether [21]. A compact ETA quartz caliber, for example, lists just 4 [24], while the Rolex Oysterquartz used 11 paired with its 32 kHz oscillator [25]. Jewels still buy longevity: the cheapest quartz movements go without, and in theory won't last as long [26]. And no, diamonds aren't better. They've been tried, but they're hard enough to wear down the pivots they're supposed to protect, which is why ruby remains the standard [26].

The jewel count itself became a marketing number almost as soon as it existed. Because it signals quality, and because some importing countries used it to set customs duties, the industry needed ISO 1112 just to define which jewels actually do something [27]. The takeaway for quartz shoppers: a jewel count tells you about how long the gears will last, not how well the watch keeps time. That job belongs to the other crystal, the one ringing 32,768 times a second while the rubies sit perfectly still.

Every car enthusiast has heard it: European cars get way better gas mileage. The cleanest way to test that is to pick one car sold on both sides of the Atlantic and follow the numbers. Enter the Volkswagen Golf GTI. The current car runs VW's EA888 evo4 2.0-liter turbo four in both markets [29][33], wears the same badge, and has been the default hot hatch for half a century. If anything should give us an apples-to-apples comparison, it's this.

Number one: 39.8 mpg. That's the official WLTP combined figure for a UK-spec GTI with the DSG gearbox [29]. The US-spec GTI, meanwhile, is rated by the EPA at 27 mpg combined [28]. On paper, the British car is 47% more efficient, and it does it while making more power: 265 PS in the UK versus 241 hp here [28][29]. Case closed, right? Not quite.

Number two: 33.1 mpg. The British gallon is the imperial gallon, 4.546 liters, while ours is 3.785. To turn UK mpg into US mpg, you multiply by 0.8327 [30]. Run the UK GTI's 39.8 through that and it becomes 33.1 US mpg. More than half the gap just disappeared with a calculator, and the car didn't change at all.

Number three: roughly 29 mpg. The rest is the test. EPA ratings are designed as estimated real-world figures, built from a series of lab tests meant to cover the conditions an average driver actually sees [31]. WLTP is friendlier, and the International Council on Clean Transportation found that by 2022, real-world fuel use for new European cars was running 14.1% higher than their WLTP numbers [32]. Apply that gap to the UK GTI and our back-of-envelope estimate lands near 29 US mpg. For a reality check, AAA's reviewer averaged 27 mpg over a week of mixed driving in a US GTI [33]. Same car, same thirst, give or take a heavy right foot and a different engine tune.

So where does Europe's real advantage come from? The showroom. UK buyers can walk in and order a Golf 1.5 eTSI 150, a mild hybrid rated at 51.4 UK mpg [35], or about 42.8 US mpg, and owners reporting real-world numbers to Honest John average 51.2 mpg, almost exactly its official figure [36]. Americans can't buy it. Volkswagen ended sales of the base Golf in the US after the 2021 model year and kept only the GTI and Golf R [34]. Scale that up and you get the whole story: the average new car in the EU weighs 1,554 kg, about 3,425 lb [37], while the average new US vehicle weighs 4,354 lb, and two-thirds of what we buy is classified as a truck [31].

The Golf isn't more efficient in Europe. Europe just buys the efficient Golf. And the next time you read a British road test and get jealous of the fuel economy, knock about 17% off the number first, then another 10% or so for the test cycle. Suddenly the Atlantic feels a lot narrower.

Thirty issues in, the thing I keep coming back to is how much of what we love is hiding in plain sight. A word on a bourbon label carries a 19th-century chemistry experiment. A number on a watch dial is a French flame and a Japanese patent decision. A window sticker is a math problem wearing a suit.

Next week, coming to you with some new reviews! See you then :)