The below technical article originally appeared in New Food Magazine and is a story about Seafood Producers Cooperative fisherman George Eliason and freezing salmon on his boat the Tammy Lin.
In Sitka, Alaska, a town of 9000 where 20% of the economy depends directly on wild salmon, there’s a well-known coffee shop decorated with images of commercial fishing. The Highliner Coffee Shop sells a coffee mug printed with a Sanskrit quote: “To judge a thing one must know the standard.” On this mug, there’s a picture of Captain George Eliason’s salmon troller the F/V Tammy Lin. The message insinuates that the Tammy Lin and Eliason’s fastidious attention to detail are the standard by which all other salmon are judged in the community. The Tammy Lin is installed with a freezer and Eliason produces frozen-at-sea salmon that once thawed in a restaurant 1000s of miles away weeks and months later, taste as if they’ve only been out of the water for an hour or so—as fresh as it gets.
The sea-frozen salmon produced on freezer boats like the Tammy Lin are a specialty product for niche buyers who know and are willing to pay a premium. This article will cover what it takes to reach that high ideal, the very pinnacle of seafood quality, the standard by which all other fish are judged. Certainly not every fisherman can achieve this standard, though George isn’t the only fisherman with an impeccable attention to detail to produce an outstanding salmon. And most customers are not able to afford the premium price demanded for this pinnacle of quality. However, as it is for any industry, we can start with the ideal of perfection and work down from there.
There are numerous resources on freezing seafood–Planning for Seafood Freezing by Edward Kolbe and Donald Kramer is one of the most extensive, well researched, and objective resources. Using Kolbe and Kramer’s principles, we’ll take a closer look at freezing seafood on a small vessel and how that helps achieve the highest standard in seafood quality.
In the seafood world, we work with a couple of basic guidelines:
1) Once a fish is pulled out of the water, a clock starts ticking and with each minute, or better stated, with each step taken, the fish has potential to lose quality. What matters more than time is care given to the fish and preservation methods.
2) Once we pull the fish out of the water, there is nothing we can do to improve the quality of the fish (assuming we don’t cover the fish’s taste with a sauce), so everything we do is to preserve its state as it came out of the water.
So, let’s say out of the water, the fish is a 10 on a scale from 1 to 10. Certainly, a fish could have a cosmetic defect like a scar made by a sea lion, or the fish might not be perceived by a buyer as a desired species or from a pristine place. For simplicity’s sake, the idea that the instant a fish comes out of the water it’s a 10 but everything that happens to it afterwards ticks off a line item on a scoring sheet, that the fish goes from being a 10 to potentially a 1. A careless cut, not getting the fish frozen before rigor mortis, or not getting every speck of blood removed from the fish are all demerits that would lower that score.
Let’s call George Eliason and the work he does on his boat the Tammy Lin the ideal to chase, the standard by which all other seafood is judged. George fishes for wild salmon with hook and line methods (also known as trolling), which in theory produce the highest quality fish. Catching a fish on hook and line gives the fisherman time to handle each fish with the most care. Each fish is bled and dressed and handled with care. Less than 5% of Alaska salmon are caught by trollers. Only about 15 percent of the trolling fleet has a freezer installed on their boat to produce the highest quality sea-frozen salmon. And few fishermen are as fastidious as George Eliason, who lives by the motto of doing things right the first time. To my questions about why you would do it his way versus another way, George is incredulous–you cannot sacrifice quality for any reason in George’s mind. Deviating from George’s methods only seems to negatively impact quality in George’s mind. Given the grading sheets for George’s frozen-at-sea salmon deliveries, it’s difficult to argue with him on matters pertaining to seafood quality. George delivers an extraordinarily high percentage of “perfect 10s,” which in the traditional seafood world are graded as “Number Ones.”
Trollers that have freezers on their boats have two distinct motivations when they decide to install a freezer on their boat as opposed to carrying ice: 1) they get on average a 20-30 % premium price for their fish versus that from an ice boat; and 2) they can extend their fishing trips to as long as 21 days. A troller keeping the fish cold with only ice must find a place to deliver fish within 3-4 days at most. They must either return to town to deliver fish to a processor or find a tender boat where the fisherman can deliver fish and stock up on ice. Having the freedom to keep fishing for 21 days saves time and money on trips back to town and opens up new territory to explore for fishing. Given the reduction in trips back and forth between town, on average a boat with a freezer can spend two more weeks fishing per season than an ice boat, which means more fish and more money for the fisherman, with or without the premium paid for sea-frozen salmon.
Here’s how that freezer works. The Tammy Lin has a 25kW genset, which runs a 25 horsepower engine, whose motor runs a compressor that keeps the air temperature in the Tammy Lin’s freezer at close to -48℉ (-44℃). This cold air brings the core temperature of the fish in the Tammy Lin’s hold to as cold as -37℉ (-38℃) within about 6 hours. Other fishermen might be content with -20℉ -(29℃). But George wonders why. Everything George aims to do is to get the fish as cold as possible and as quickly as possible. The ideal is to preserve the fish in a frozen state before it reaches rigor mortis. Cleaned and pressure bled with a pipette, the fish caught on a freezer boat are put in the freezer hold while the fish’s heart is still beating on the deck of the boat Physiologically speaking, time stops. Any of the fish’s flesh breakdown halts at this point, including key enzymatic processes that occur at a cellular level which affect texture and taste. The fish literally becomes frozen in time within hours, much faster than any fish sold in most fresh market situations can reach its customers.
The Tammy Lin has a 17,000-pound capacity hold and once it’s filled George can return to town to deliver the fish. George estimates that the freezer burns a gallon of diesel per hour, but of course gets more efficient with more fish in the hold, as the ambient temperature lowers.
George has a “custom” set-up. A fisherman could also get a “drop-in” freezer set-up from a company like Integrated Marine Systems (IMS) out of Seattle, Washington. IMS manufactures and helps install freezers for fishing vessels.
A critical point is having an extremely well insulated hold. Fishermen adding freezers to their boats with poorly insulated holds not only run less efficiently, but cause frost build-up and their fish won’t reach those colder temperatures as quickly, sacrificing quality. The Tammy Lin is so well insulated that, with no air leaks, defrosting the hold causes the hatch to pop open.
For salmon trollers, blast freezers blowing freezing wind at 10 knots over trays of frozen fish, are the preferred freezing system, but for some fishermen seeking albacore tuna, a number prefer the brine system with a mix of frozen seawater. A shrimp fisherman will use a plate freezer. It must be said that there are a number of schools of thought, as scientists at the Oregon State University’s Seafood Lab have studied. Edward Kolbe, Cormac Craven, Gil Sylvia and Michael Morrissey’s “Chilling and Freezing Guidelines to Maintain Onboard Quality and Safety of Albacore Tuna” runs through the pros and cons of each freezing method and the most critical principles to consider when running a freezer on a tuna fishing vessel.
The guiding principle, as it is with frozen-at-sea salmon, is getting the fish as cold as possible and as quickly as possible. In the case of tuna, which little does the average public know is a warm-blooded creature, their body temperature coming out of the water might be as high as 80℉ (27℃) at the core. Having a deck tank with chilled sea water helps ensure that the fish gets cold (ideally to 40℉) as quickly as possible before putting it in the freezer, which minimizes temperature fluctuation in the hold, reduces freezer energy load, and improves flesh quality. Maintaining colder temperatures minimizes autolytic degradation that can cause histamine build-up in a warmer water fish like tuna. Warm fish bring ambient heat, impeding the freezer’s efficiency and its ability to keep all fish in the hold as cold as possible. This chill rate will depend also on fish size, ambient air temperature or the water temperature in a deck tank and a “rapid rate” depends on the eye of the beholder. The heat transfer coefficient will affect freezing time and an appropriate catch rate should be determined for the vessel’s freezing system and hold. The initial freezing point of a fish will depend on its moisture content but is typically around 28 to 30℉. Freezing too slow causes dehydration, increased enzyme activity, decreasing the quality of the fish and causing spoilage, and protein denaturation, meaning that muscle proteins have unraveled from their coiled state, decreasing their ability to hold water molecules. Upon thawing, the water drains away as drip loss.
As noted above, once the fish is harvested there is no way to improve its quality, but you can slow down the rate of quality deterioration by properly handling the fish on board, freezing it quickly, and storing the fish at a temperature that does not fluctuate. This is the ideal for frozen seafood—the proverbial “perfect 10.”
There are a number of technical barriers to entry to a salmon fisherman installing a freezer on his or her boat. Firstly, some fishermen don’t want to stay out the 21 days that the freezer allows. Those fishermen forgo the premium dock price because there is certainly a romance to not having to hear a generator run all night. George “sleeps with one eye open” while fishing, so the noise of a generator running all night doesn’t bother him. In addition, George hired an extra hand when he installed the freezer because of the extra steps required. The Tammy Lin runs a crew of 3, including the captain. The extra hand makes the “big days” of 400 fish much more do-able. And some freezer boat fishermen have noted that there are 18 distinct steps one must take with the fish before putting it into the hold. An average to good day of 100 fish or so is manageable without the extra help, but boats that run only a crew of two can end up sacrificing quality or end up burning themselves out working a succession of 20-hour work days, which would be the norm in an Alaska summer salmon season. George’s deckhands work quickly and carefully, cutting heads off, making belly incisions, gutting the fish, pressure bleeding it with a pipette, and carefully stowing it on aluminum trays, using a batch system to make it goes as efficiently as possible. In addition to cleaning and pressure bleeding with a pipette pre-rigor, George has at least three hoses running, cleaning the deck.
Once a fisherman installs a freezer on their boat, they have to become licensed as a “direct marketing fisherman,” and their boat essentially becomes a “portable processor” with a HACCP plan and paperwork to fill out 4 to 6 times a day. George notes numbers of fish caught, parts per million in the bleach solutions, where they dumped their head, etc. As a processor, George needs to have a tarp over his deck, his processing area, whereas ice fishermen can work with the sun (or other elements) above them. Having to comply with regulations from the Department of Environmental Conservation and even Homeland Security becomes part of the workday for a direct marketing fisherman producing a frozen-at-sea product. More taxes to pay and regular inspections also become a concern.
Other little details matter, too. George says he goes through a lot more knives on his freezer boat, as the extra steps require more cutting. An ice boat will leave town with a few thousand pounds of ice that serves as a stabilizing ballast. George added some rolling stabilizers to help his freezer boat when leaving town with an empty hold. Each light in the freezer hold needs to be covered, should it be bumped and broken it will not contaminate the fish with broken glass. He puts a 6% seawater glaze on his fish and maintains a bleach solution in which fish are dipped.
Probably the biggest, somewhat unspoken barrier to entry to installing a freezer onto a small fishing vessel, is finding a market for a fish of that quality. Restaurants rarely have a space to thaw out a frozen-at-sea fish and might only take a few fish at a time. Fewer chefs have the ability to break down a whole fish. Nevertheless, when put to blind taste tests with fresh-never-frozen salmon, a frozen-at-sea salmon is going to be as good as a fish that has just been pulled out of the water. You also get the added benefit of more efficient, hassle-free transportation once it’s frozen, and a lot longer shelf life. It’s a “perfect 10” when done right. The troll-caught frozen-at-sea wild salmon is a standard by which all other seafood is judged. Reaching that standard isn’t for the feint of heart.
*Note: George Eliason is retiring this year. “After 50+ years on the ocean, why not get off? I’ve pretty much seen and done all that I wanted.” George’s attention to detail will be passed on to future generations.