The Great Molasses Flood: A Crisis of Fermentation?
By Lydia Noyes
Shutterstock/Halil ibrahim mescioglu
It’s one of the strangest disasters in history, a story so far-fetched it seems like a fantasy. But for those unfortunate enough to witness it firsthand, the sticky flood of sweetener that swamped Boston’s oldest streets was far from fictional. In the early 20th century, a giant tank of industrial molasses ruptured in the North End, triggering a calamity that left 21 dead and 150 injured, and created millions of dollars in property damage.
The biggest question in the wake of this tragically avoidable accident is what happened to bring about the Great Molasses Flood of 1919. Could everything be chalked up to poor management, or was there something else fermenting beneath the murky molasses surface?
The setting. In 1915, the Purity Distilling Company built a tank in Boston’s North End to store molasses imported from the Caribbean. This enormous steel tank measured 50 by 90 feet and had the capacity to hold 2-1/2 million gallons of molasses, enough to fill 3-1/2 Olympic-sized swimming pools. It provided a temporary holding space for the syrup before it could be sent across the river to an ethanol distillation facility, where it was eventually used to feed the insatiable wartime demand for dynamite, bombs, and other munitions.
The incident. January 15, 1919, started unseasonably warm, around 40 degrees Fahrenheit. Just after 12:30 p.m., downtown workers, who were outdoors enjoying the break in wintry weather, heard a piercing staccato sound coming from the harbor. It was the rivets from the molasses tank shooting off under pressure. A dull roar followed, and the tank’s steel sides ripped open, spilling more than 2 million gallons of warm molasses down Commercial Street in a wave that some reports say crested at 15 feet.
The damage. The black tide of sweetener raced through the North End’s populated neighborhoods at 35 miles per hour, building up enough momentum to tear buildings from their foundations, smash homes apart, and snap the supports off elevated train tracks. Within minutes, the syrup had overwhelmed two city blocks and caused what would be more than $100 million today in property damage. But worse still was the human cost; the flood killed 21 people and injured more than 150 others.
The Great Molasses Flood made national news the very next day, and eclipsed reports about the same-day passing of the 18th Amendment: Prohibition. Decades later, many claim to still smell molasses in Boston’s streets on hot summer days.
The cleanup. Rescue efforts continued for days, and the spill stained Boston Harbor brown for weeks. Cleanup efforts took more than 80,000 man-hours, and it was four months before the last body attributed to the flood was found lodged underneath the pier.
Molasses’s high viscosity created more force on impact during the flood, and made rescue attempts much harder. And as the temperature dropped that evening, the molasses firmed to the point that many victims became stuck within it, further hindering rescue attempts.
The case. U.S. Industrial Alcohol, Purity Distilling’s parent company, was quickly taken to court over the disaster. The trial lasted for six years and heard thousands of witness testimonies in an attempt to trace the incident back to its root cause.
The suspect. The court considered whether natural fermentation principles had a role in the accident. A new shipment of hot molasses had been added to the tank just two days before the explosion, which mixed with the cold contents already inside. Molasses’s high sugar content gives it a natural propensity to ferment, creating carbon dioxide as a byproduct. The hot molasses and unseasonably warm weather on the day of the explosion may have sped up the fermentation process and built up enough pressure within the tank that it burst apart.
The cause. Though fermentation likely did play a part, it was eventually determined that the primary reason for the disaster was shoddy tank construction.
The culprit. U.S. Industrial Alcohol treasurer Arthur Jell, a man without any technical, architectural, or engineering experience, managed the original building project. In order to quickly meet the rising demand for World War I weaponry, he hastily approved the tank’s plans, and ignored many traditional safety protocols during the construction process. Though it was standard practice to test a molasses tank’s strength by first filling it with water, Jell never had the tank filled above the bottom 6 inches before giving his approval for its use.
This slapdash design was only the beginning of the tank’s construction problems. The steel used wasn’t made with enough manganese, which made it brittle at any temperature below 59 degrees. Flawed rivet designs compounded the problem, and this was where the first cracks formed.
The summer before the accident brought sweltering temperatures to Boston, and with them, resident complaints that the tank was springing leaks. The Purity Distilling Company took action, not by reinforcing the tank or patching the holes, but by painting it rust-brown so the molasses spills blended in. This fixed nothing, as demonstrated by the neighborhood children regularly scampering up to the tank, pails in hand, to collect the sweet liquid as it dripped out.
In many ways, it was a miracle the tank lasted as long as it did before it burst. Though molasses had been poured into the tank on 29 separate occasions, it had only been filled to capacity four times, the last of which was the day before it exploded.
The aftermath. In 1925, the court ruled that U.S. Industrial Alcohol was responsible for the disaster. The company paid the flood victims and their families $628,000, the equivalent of $9.2 million today.
While the company was never prosecuted with criminal charges, the man-made disaster inspired survivors to push for safer zoning legislation in their North End neighborhoods, and in Massachusetts more broadly. Just one week after the disaster, Massachusetts State Representative Edward Scigliano introduced a bill that required any storage tanks containing liquid or gas to be kept at least 1,650 feet away from residences. Shortly thereafter, the Boston Building Department mandated all calculations made by engineers and architects needed to be filed with plans before they could be approved.
Inspired by this political organizing, other states soon followed suit to better protect their citizens from future industrial accidents. This started a national precedent for companies to take responsibility for public safety, rather than passing on the risk to poor immigrant communities without the political power to fight them.
Today, the site of the Great Molasses Flood bears little resemblance to the wharf it used to be. Within years of the accident, advancing war technology made the process of distilling molasses for alcohol outdated, and the industry faded away. Today, a public park on the waterfront fills the scene instead, with a small plaque commemorating the event and the resilient North End citizens who turned a disaster in their neighborhood — caused not by fermentation gone wrong, but by chronic industry oversight — into an opportunity to advocate for their safety and for the safety of future residents of Boston and beyond.
While the smell of molasses may first spark thoughts of holiday cookies today, it once served a far less celebratory purpose — weapon manufacturing. Factories, such as the one in Boston run by the Purity Distilling Company in the early 1900s, distilled molasses to create ethanol. This was a key component in creating munitions during World War I.
To convert molasses into ethanol, distillers rely on fermentation. Molasses is mixed with water and yeast, then fermented to produce ethanol and carbon dioxide. Later, the produced ethanol is separated from the carbon dioxide. Fermentation, being exothermic, also gives off heat. After the Great Molasses Flood, people first surmised that the molasses in the tank had been fermenting, and since the ferment’s carbon dioxide and heat had nowhere to go, the result was a pressure cooker that exploded through the North End. This was ultimately an incorrect — but understandable — conclusion.
Shutterstock/Halil ibrahim mescioglu
What’s in a Phrase?
Many people have heard the phrase “slow as molasses in January,” a simile that describes something or someone moving incredibly slowly, just like thick molasses would in the deep cold. Though it’s not agreed upon exactly when this phrase started entering conversations, some attribute it to at least the 1800s. So, even though molasses swept through Boston in January 1919, oddly enough, it wasn’t what created the phrase. And why would it? After all, this molasses sped 35 miles per hour through the North End, which wasn’t slow at all.
Don’t Want a Fermentation Mess?
Many home fermenters have personal experience with bursting fermentation creations. Any time a product that’s actively fermenting is sealed too tightly, the carbon dioxide produced has nowhere to go. The result? Burst jars of sauerkraut, kimchi, and even sourdough starters.
Thankfully, there’s an easy way to avoid this outcome. All you need to do is “burp” ferments by either loosening the lid every few days, or install an airlock to let the gas escape without risking contamination.
Shutterstock/Halil ibrahim mescioglu
The Merchant of Death
How does the founder of one of the most well-known international honors connect back to the Great Molasses Flood? Before he was known for the Nobel Prize, Alfred Nobel, a brilliant chemist, engineer, and inventor, patented dynamite in 1867. Then, as the story goes, Nobel read an obituary in 1888 that mistakenly announced his death instead of his brother’s. The obituary, written by an obvious deep critic of the dynamite inventor, reported that “the merchant of death is dead.”
Horrified by the reputation he might leave behind, Nobel became a philanthropist. Eventually, the Nobel Prize was established in 1895 based on Nobel’s desire to honor advances of academic, cultural, and scientific significance with his fortune. However, his earlier work won’t be forgotten. During the early 1900s, molasses was distilled to create the ethanol that would be included in dynamite’s production, the same molasses that smothered Boston’s North End in a strange and damaging tragedy. Today, the site of the Great Molasses Flood bears little resemblance to the wharf it used to be. Within years of the accident, advancing war technology made the process of distilling molasses for alcohol outdated, and the industry faded away. Today, a public park on the waterfront fills the scene instead, with a small plaque commemorating the event and the resilient North End citizens who turned a disaster in their neighborhood — caused not by fermentation gone wrong, but by chronic industry oversight — into an opportunity to advocate for their safety and for the safety of future residents of Boston and beyond.
Lydia Noyes is a freelance writer and hobby farmer on a 33-acre property in southwest Michigan. You can find her at First Roots Farm.
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