Evan Sung/The New York Times

St. Patrick's Day themed meal

March 20, 2022

The Science Behind St. Patrick’s Day Cuisine

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This past Thursday a series of St. Patrick’s Day celebrations filled with shamrocks, green madness and Irish cuisine began. From soda bread to beer, this famous holiday is known for its unique dishes –– and each tells its own food science story.

Corned beef is one of the staples of St. Patrick’s Day in America. The “corn” here does not refer to a corn on the cob. Instead, “corn” refers to the large salt crystals on the beef during a five to eight day curing process. 

During this process, the salt, which is made of charged ions, disrupts the electrostatic interactions in protein structure. This causes the protein to unravel, giving it a more tender texture. 

Sodium nitrite — commonly in pink curing salt or Prague powder, used for many deli meats — is also used in the production of corned beef for distinctive quality purposes such as color and flavor. 

According to Prof. Abigail Snyder, food science, including nitrates as preservatives, helps promote food safety and gives corned beef its characteristically vibrant pink color. 

Without sodium nitrite, corned beef and other deli meats would remain brown without the savory flavor associated with cured products.

The flavorful corned beef is often paired with a side of soda bread, which has a chewy crust and soft, crumbly interior –– a result of the short mixing time which reduces the amount of gluten, impairing the dough’s ability to rise. 

Unlike regular bread, soda bread consists of sodium bicarbonate, or baking soda, as a leavening or rising agent, instead of yeast. The basic baking soda, combined with acidic buttermilk, creates a chemical reaction that produces carbon dioxide. The carbon dioxide then produces bubbles in the dough and causes the bread to rise. 

To complete the meal, a special Irish beverage is served as a refreshing drink. Irish stout, typically used to make green beer, is a staple of St. Patrick’s Day. While the process of dying beer green only involves the addition of green food coloring, the practice of beer making and flavor composition is more complicated. 

For example, Irish stouts are known for their roasted malt, coffee aroma and hint of sourness, which arise from the malted barley and other components in brewing. 

Four ingredients are needed to make this type of beer: grain, water, hops and yeast. 

Hops, a flowering vine that produces oils that have antimicrobial properties, is what largely provides the bitterness flavor. Different varieties of hops create unique aromas in beer. In Ithaca, several breweries use fresh hops to make their beer.

“If you went down [Tower Road] to Hop Shire, one of the local breweries, hops are grown right in the front along the road,” Prof. Patrick Gibney, food science said. 

During the brewing process, the water and various types of grains –– such as barley, which is found in Irish dry stout –– are heated. This allows plant seed enzymes to degrade the starch into simple sugars, serving as a food source for the yeast to make ethanol. These grains  are then toasted and produce an assortment of combinations that yield specific flavors such as spiciness or chocolatey flavors. 

During the brewing process, the water and grains such as rice, wheat –– or in Irish Guinness –– barley, are heated allowing plant seed enzymes to degrade the starch into simple sugars which serve as food for the yeast to make ethanol.

Following brewing, the “wort” mixture is filtered and another layer of aroma is added through pitching or adding in diverse yeast strains. Different strains lead to a production of two categories of beer: lager and ale

Lager is a bottom fermenting yeast at cold temperatures. However, ale –– such as the irish stout –– is top fermenting yeast at warm temperatures.

While ale uses saccharomyces cerevisiae strains, lager uses a hybrid strain between Saccharomyces cerevisiae and saccharomyces eubayanus. These yeast strains in beer, unlike in wine, use maltose grain sugars, said Gibney. 

These unique components give various types of beer, such as the Irish stout drink, their special aroma and flavor.