Lutefisk:Secrets of the Taste, Texture, andA roma Revealed by Scanning Electron Microscopy Howard D. Mooers & B. Bandli, University of Minnesota Duluth Introduction Every Advent we entered the purgatory of lutefisk, a repulsive Lutefisk (lyefish) is a traditional delicacy gelatinous fishlike dish that tasted of that today is generally served as an Advent soap and gave off an odor that would gag celebration treat for the whole family, but was a goat. We did this in honor of once a staple of Scandinavian diets. During the Norwegian ancestors, much as if late 1800s and early 1900s, Scandinavian survivors of a famine might celebrate immigrants brought traditional foods like their deliverance by feasting on elm barIc. lutefisk to the USA. The focus of this paper is I always felt the cold creeps as Advent on secrets of lutefisk but is based primarily on approached, knowing that this dread anecdotal data from Minnesota; however, we delicacy would be put before me and I~d fully expect the data to represent Scandinavian be told, ((Just have a little." Eating a lzttle immigrant communities through North America. was like vomiting a little, just as bad as a Children growing up in rural Minnesota spend lot. the year in anticipation of this seasonal feast. This seasonal delicacy is commonly found in all After years of tabulating anecdotal evidence, fine markets from October through December in the authors have identified a correlation areas where large numbers of people of between the preparation and cooking methods Scandinavian descent live. The testimonials of of lutefisk and the general tolerance of lutefisk true lutefisk eaters are all you need to dish up eaters. To elucidate the underlying and dive in. For example: biochemistry, scanning electron microscopy was ((Can you pass that bowl of lutefzsk again? I employed. Following a successful ~utefis~ need another plate. " (Fritz Larson, personal offering at a Department of GeolOgIcal SCIences communication. ) holiday potluck dinner, sample of the lutefisk ((Elsie, are you having lutefzsk again were immediately imaged with SEM. tomorrow? I am free. " (Edla Mooers, personal The results were surprising and communication. ) unexpected. Lutefisk has a unique texture that However, not everyone has a tolerance for is dominated by 3 distinct cellular structures. the fine taste and aroma of this culinary Herein we refer to these as flavor cells, texture delicacy (see Lutefzsk Lament by Boone and cells, and aroma cells, and speculate on the Erickson or Oh, Lutefzsk by Stangland and Lee). relation to preparation and cooking methods. Keillor (1990) sums up the thoughts of many as follows: Figure lA: Drying cod on racks in Norway Figure 1B: Method of recon­ s-tituting lutefisk. <6J1R 16 Background Steaming - Lutefisk is salted, placed in a tightly-covered pan, and steamed in its own Drying and Reconstituting LuteflSk - Prior to liquid for 20 minutes or so. the general availability of refrigeration, fish was Baking - Lutefisk is placed in a baking dish preserved by drying (Figure 1A). Types of fish (often lined with aluminum foil) and baked at and the drying methods varied by location and 250°F - 300°F for 40 minutes or so. cultural tradition but generally drying was Boiling - Water is brought to a rolling boil accomplished on racks by the Sun, cold dry air, and lutefisk, cut into small pieces, is placed in or wind. Once dry, the fish could be stored for the boiling water. Return the water to a boil long P1riods of time while being shipped to local and cook for 5-8 minutes. Care must be taken or distant markets. Dried fish is then not to overcook as the lutefisk will fall apart. consumed directly or it can be reconstituted by Eating - Once cooked by any method, the rehydration. In Scandinavia, the most readily lutefisk is ready for serving. Traditionally the available types of commercially available fish white gelatinous fish is served over mashed were cod, haddock, whiting, and torsk potatoes and covered in white sauce with (en. wikipedia. orgjwikij LisCoCfish_in_Sweden) . melted white butter. The only allowable Although there are a number of methods for seasonings are salt and pepper; the pepper reconstituting dried fish, lutefisk is prepared gives the meal color. from the dried fish in a very specific multi-step process. The first step is to soak the dried fish in a lye solution for several days with frequent Methods changes of the water (Figure 1B). The lye Methodology for this investigation consists solution breaks down the tough dried cellular of compiling anecdotal data on lutefisk eaters, structure created by the drying process; it also cooking method, and the comments of adjacent reduces the protein content. Care must be non-Iutefisk eaters. These data were compiled taken not to let the lye treatment go on too long mainly from dinner napkins and back-of-the­ because saponification may occur and convert hand scribbles. lipids to soap (Bodenstein 1961). When Determination of cellular structure of the prepared correctly, the result is a gelatinous lutefisk was determined by SEM. Samples were substance with a pH of about 12 that quite taken from leftovers after a departmental resembles fish. The next step is to rinse the lye holiday potluck dinner. Lutefisk served as the from the fish by soaking for several days in main course surrounded by a variety of hot dish fresh water with at least daily water changes. offerings. Samples were mounted and loaded After these final rinses the lutefisk is ready for into a JEOL JSM-6490LV variable pressure delivery to markets. scanning electron microscope. Samples were Traditionally, lutefisk was delivered dry to scanned at low vacuum so that they could be markets. Once there it was stacked like left wet to preserve the edible nature of the cordwood on tables or, alternatively, leaned samples. against the side of the market on the sidewalk. There was no need for great care in the storage because the impending lye treatment would Results 41 years of anecdotal data are compiled in eliminate any living matter. D. E. Mooers Table 1. Comments were recorded in many (personal communication) often described the forms but broken down into several main stacked lutefisk as a common stop for dogs. comments. These comments were then Preparation and Cooking of Lutefisk - Once translated by one of the authors (HM) into the 3 reconstituted, lutefisk is purchased and main categories. For lutefisk lovers' comments brought home. Great care must be taken at the 3 categories are: Pretty Good, You Betcha, this point to store the lutefisk in air-tight and Uffda. The bystanders comments are also containers or an adjacent building as the odor broken into 3 categories: Just Dizzy, a series of of fishy-lye can be pungent (Keillor 1990). gagging sounds, and Uffda (Uffda can be used To prepare for cooking, the lutefisk is again as a superlative for both positive and negative rinsed thoroughly. Although cooking methods comments). A summary of the results for each vary, each traditional Scandinavian cook has cooking method are tabulated in Table 2 and their favorite: represented graphically in Figure 2. 6J1R 17 QJ r;:: U "0 Lutefisk lovers' comment Translation C § i Aw Geez Pretty Good ~ r,:: ! ~ u1;; Oh don't ya know Pretty Good 0.. "" ~ ::J Pretty Good Pretty Good E 52 You Betcha You Betcha Uffda Uffda ~ II OMG Uffda :3 ~ t ____ __ _ .. __ _ _. __ __ LOL You Betcha Steaming Baking Boiling Figure 2. Summary of data from Table 2. Bystanders' comments Translation Not fit for Man nor Beast Just Dizzy and contain vacuoles. However, among the [speechless] Uffda cells outside the massive zone there are 2 [heard through bathroom door] Uffda distinct textures. On the left of Figure 3B is a Uffda Uffda network of fibrous protein with irregular Argh Gagging vacuoles. On the right side of Figure 3B is an Ahem ... Just Dizzy area of smooth textured protein with large Not as bad as last year Just Dizzy round vacuoles. Humph \ Gagging Discussion Table 2. Cooking preference Although the data are anecdotal there is a clear correlation between cooking method and Steaming Baking Boiling Lutefisk Lovers' Response both lutefisk lover and bystander response. Pretty Good 89% 78% 14% Uffda responses by lutefisk lovers are far more You Betcha 8% 17% 29% common with the boiling method of cooking Uffda 3% 5% 57% than either steaming or baking (Figure 2), whereas Uffda responses by bystanders are Bystanders' Response most common with steaming or baking (Figure Just Dizzy 4% 8% 64% 2). Gagging 10% 10% 26% These data can now be interpreted within Uffda 86% 82% 10% the context of the cellular structure of the lutefisk. We interpret the dense fish fiber to be Scanning electron micrographs are shown the texture cells (Figure 3B). These are the cells in Figure 3. Figure 3A is a 350x magnification that give the lutefisk its unmistakable of a fish fiber. Increasing the magnification to gelatinous texture. The network of fibrous 2500x instantly reveals 3 types of cellular protein with irregular vacuoles is interpreted as structure (Figure 3B). The dense fish fiber in the flavor cells (Figure 3B). These cells likely the center of Figure 3B can be distinguished release the portion of the lutefisk that brings from the 2 other textures by its more massive pleasure (You Betcha or Uffda response) to appearance. Cells on either side are more open lutefisk lovers. The large round open cells of the smooth-textured are unmistakably Figure 3A. 350x enlargement of lutefisk fiber. 3B. 2500x enlargement of lutefisk showing the texture, flavor, and aroma cell locations. 6l1R 18 "the cells that produce the pungent aroma North wind, can be contaminated.