My new article, “Prohibition and Percolation: The Roaring Success of Coffee During US Alcohol Prohibition”, is now published in Southern Economic Journal. It’s the first statistical analysis of coffee imports and salience during prohibition. Other authors had speculated that coffee substituted alcohol after the 18th amendment, but I did the work of running the stats, creating indices, and checking for robustness.
My contributions include:
National and state indices for coffee and coffee shops from major and local newspapers.
A textual index of the same from book mentions.
I uncover that prohibition is when modern coffee shops became popular.
The surge in coffee imports was likely not related to trade policy or the end of World War I
Both demand for coffee and supply increased as part of an intentional industry effort to replace alcohol and saloons.
An easy to follow application of time series structural break tests.
An easy to follow application of a modern differences in differences method for state dry laws and coffee newspaper mentions.
Evidence from a variety of sources including patents, newspapers, trade data, Ngrams, naval conflicts, & Wholesale prices.
Generally, the empirical evidence and the main theory is straightforward. I learned several new empirical methods for this paper and the economic logic in the robustness section was a blast to puzzle-out. Finally, it was an easy article to be excited about since people are generally passionate about their coffee.
Bartsch, Zachary. 2025. “Prohibition and Percolation: The Roaring Success of Coffee During US Alcohol Prohibition.” Southern Economic Journal, ahead of print, September 22. https://doi.org/10.1002/soej.12794.
Economists rely on trade data. The historical Foreign Commerce and Navigation of the United States reports detailed monthly figures on imports, exports, and re-exports. This dataset spans decades, providing a crucial resource for researchers studying price movements, consumption patterns, and the effects of war on global trade.
The U.S. Department of Commerce compiled these reports to track the nation’s commercial activity. The data cover a vast range of commodities, including coffee, sugar, wheat, cotton, wool, and petroleum. Officials recorded trade flows at a granular level, enabling economists to analyze seasonal fluctuations, wartime distortions, and postwar recoveries. Their inclusion of re-export figures allows for precise estimates of domestic consumption. Researchers who ignore re-exports risk overstating demand by treating imports as goods consumed rather than goods in transit.
I’ve written about coffee consumption during US alcohol prohibition in the past. I’ve also written about visualizing supply and demand. Many. Times. Today, I want to illustrate how to use supply and demand to reveal clues about the cause of a market’s volume and price changes. I’ll illustrate with an example of coffee consumption during prohibition.
The hypothesis is that alcohol prohibition would have caused consumers to substitute toward more easily accessible goods that were somewhat similar, such as coffee. To help analyze the problem, we have the competitive market model in our theoretical toolkit, which is often used for commodities. Together, the hypothesis and theory tell a story.
Substitution toward coffee would be modeled as greater demand, placing upward pressure on both US coffee imports and coffee prices. However, we know that the price in the long-run competitive market is driven back down to the minimum average cost by firm entry and exit. So, we should observe any changes in demand to be followed by a return to the baseline price. In the current case, increased demand and subsequent expansions of supply should also result in increasing trade volumes rather than decreasing.
Now that we have our hypothesis, theory, and model predictions sorted, we can look at the graph below which compares the price and volume data to the 1918 values. While prohibition’s enforcement by the Volstead act didn’t begin until 1920, “wartime prohibition” and eager congressmen effectively banned most alcohol in 1919. Consequently, the increase in both price and quantity reflects the increased demand for coffee. Suppliers responded by expanding production and bringing more supplies to market such that there were greater volumes by 1921 and the price was almost back down to its 1918 level. Demand again leaps in 1924-1926, increasing the price, until additional supplies put downward pressure on the price and further expanded the quantity transacted.
We see exactly what the hypothesis and theory predicted. There are punctuated jumps in demand, followed by supply-side adjustments that lower the price. Any volume declines are minor, and the overall trend is toward greater output. The supply & demand framework allows us to image the superimposed supply and demand curves that intersect and move along the observed price & quantity data. Increases toward the upper-right reflect demand increases. Changes plotted to the lower-right reflect supply increases. Of course, inflation and deflation account for some of the observed changes, but similar demand patterns aren’t present in the other commodity markets, such as for sugar or wheat. Therefore, we have good reason to believe that the coffee market dynamics were unique in the time period illustrated above.
*BTW, if you’re thinking that the interpretation is thrown off by WWI, then think again. Unlike most industries, US regulation of coffee transport and consumption was relatively light during the war, and US-Brazilian trade routes remained largely intact.
Why does the average drinker consume alcohol? There are plenty of reasons, one of which is social. Alcohol, while inhibiting clarity, precision, and discretion, is a social lubricant. If you’re one of those drinking, then it’s enjoyable to be around other drinkers. Also, people build the habit of drinking *something* while socializing. We all know that prohibition resulted in bootlegging and tainted cocktails. But what were the legal alternatives? One was that you could purchase grape juice and make your own wine (that’s a story for another time). Another is to switch to another drug.
Alcohol is a depressant and arguably the most popular one in the US. It’s not a clear substitute for alcohol in terms of its direct effects on the body. However, it’s a liquid, safe, and tasty. That make is a good candidate for satisfying the physical urge to imbibe. But, importantly, it is also a social drug. People would get so hopped up on coffee and feed off of one another’s high that Charles the II of England banned coffee houses in order to prevent seditious fomentation. This brings us to an important characteristic of coffee. It’s a stimulant. You’d think that a stimulant would not be a substitute for alcohol. If anything, one might think that they are complements. Coffee helps to provide that kick in the pants after having an enjoyable night. But, the social feature makes coffee a good candidate to substitute alcohol, should the times be dire.
Illegal activity aside, people wanted an outlet for their physical and social proclivities. They wanted intoxication. Coffee provided exactly that. Conveniently, the continental US didn’t grow any of its own coffee. That means that imports and domestic consumption have a tight relationship.
I make a hobby of reading, and sometimes acting on, investment advice, particularly regarding high-yielding securities (many of my holdings are now yielding over 10%/year). One of the best authors on the Seeking Alpha investing site writes under the name of Colorado Wealth Management. He mainly writes on REIT (real estate investment trust) stocks, but recently opined on the wisdom of raising interest rates to combat inflation regarding some of the major components of CPI.
His article, Why High Yields Will Be Popular Again, may be behind a paywall for some readers, so I will summarize some key points. He kind of sidesteps the influence of massive federal deficit spending that injected trillions and trillions of new dollars into the economy for COVID, which I think has been the major driver for this inflation; and the reignited deficit spending which is already on the books for November and likely even huger for December of this year. However, he does make some interesting (and new to me) points regarding food prices in particular.
He sees the price 2021-2022 price increases in some major food items as being driven by supply constraints, rather then by excessive demand. Specifically eggs, coffee, and vegetable oils have been hit by exogenous factors which have constrained supply; raising interest rates will not help here, and may even hurt if higher rates make it harder for farmers to recover and re-start high production. I’ll transition to his charts and mainly his excerpted words, in italics below:
Avian Flu, Culled Hens, and the Price of Eggs
The background here is that tens of millions of chickens, including egg-laying hens, have been deliberately killed (“culled”) this year in an attempt to slow the spread of avian flu. This, of course, cuts into the egg supply and raises egg prices. We went through a similar cycle in 2015 with avian flu, where culling led to a rise in egg prices, but then prices fell naturally as a new crop of chicks grew into egg-laying hens. Similarly, the current shortage in eggs should correct itself:
Raising interest rates has never produced additional eggs. Raising interest rates and driving a recession (with larger credit spreads) only makes it more difficult for farmers to get the funding necessary to replace tens of millions of hens that were culled to slow the spread of the avian flu….If interest rates don’t work, what will? The cure for high prices is high prices. We can see how it played out with the Avian flu in 2015:
Is Jerome Powell going to lay even one egg? Probably not.
Are farmers going to focus on turning their chicks into egg-laying hens? Absolutely.
Since eggs go into several other products, it drives inflation throughout the grocery store. Even if a product doesn’t use eggs, the drop in egg production means more people eating other foods.
Drought in Brazil and the Price of Coffee
Coffee prices have been rising rapidly. Well, domestic prices have been rising rapidly. Global prices actually declined since peaking in February 2022:
So, what drove the price up? Brazil normally produces over 35% of the world’s coffee and bad weather in Brazil (not to mention the pandemic impacts) drove dramatically lower production in 2021. As the shortfall in production became evident, global prices began rising rapidly. That’s why the global [wholesale] prices were ripping higher in 2021, not 2022. However, [retail] consumers are seeing most of the impact over the last several months.
War in Ukraine and the Price of Sunflower Oil
Margarine requires vegetable oil. Soybean, palm, sunflower, and canola oil are the key ingredients. What country produces the most sunflower oil? Ukraine. This is one of several inflationary impacts of the war. You can see the impact of reduced supply in the following chart:
Government Bungling in Indonesia and the Price of Palm Oil
What happened to palm oil? How could it soar so much and then fall so hard?
The first issue is that dramatic increases in the price of fertilizer made production more expensive. … That contributed to a reduction in supply. However, Indonesia is the world’s largest exporter of palm oil. Yet exports of palm levy were subject to a huge levy. That made exporting far more expensive. Despite the levy, it was still worth producing and exporting palm oil. Then the Indonesian government decided to simply ban exports over concern about higher domestic prices. Banning exports for a country that produces 59% of the world’s total palm oil exports had a predictable impact.
If you guessed that the supply of palm oil couldn’t be sold domestically, you’d be right. The ban was lifted. However, it was only after:
“High palm oil stocks have forced mills to limit purchases of palm fruits. Farmers have complained their unsold fruits have been left to rot. There were 7.23 million tonnes of crude palm oil in storage tanks at the end of May, data from the Indonesian Palm Oil Association (GAPKI) showed on Friday.“
With palm oil prices at all time-record highs, nearly triple the level from two years prior, the supply was left to rot. Each business tried to make the best decision they could, given the ban on exports. Rather than record profits for mills and record profits for farmers, the produce was wasted. That’s supply constraints for the global market, and it destroys the local economy.
Global prices are plunging now as mills seek to unload their storage. As bad as the higher prices were for the rest of the world, no one suffered worse than the farmers whose product became worthless as a result of government failure.
Contrary to today’s popular opinion, higher interest rates won’t do anything to improve production of vegetable oil.
There are lots of fun coffee shops in Birmingham. I’m going to limit this list geographically to make it a “crawl” that you could potentially bike around. I’ll list the cute places I know that are between Railroad Park downtown and Samford University south of Birmingham.
Starting at the North end, coffee shops that border Railroad Park:
Economist Writing Every Day 