After learning about dry aging and purchasing a UX1000 from DryAger, my next task was to learn the limits of dry aging fish. I had so many questions:
What does dry aging do to the flavor?
What is the minimum time you can dry age to be effective?
Where is the point of diminishing return?
What is the maximum time you can dry age before the product spoils?
What is the optimal time to dry age each fish?
I had my questions. Next, I used my science background to for a hypothesis: The dry ager would obviously dry out the fish alittle bit and the enzymes in the fish will transform the flavor over time. I would need to pick a bigger fish I could process and hang but I would also need the fish to be small enough that I could fit several fish in the case at the same time. Additionally, I would need to pick something with good intermuscular fat content so it wouldn't taste dry or like jerky when slightly dehydrated.
I decided to do an experiment with one of my favorite fish, Big Glory Bay king salmon. Firs off, we get the fish in super fresh, usually no more than 3 days out of the water. One time I received a fish so fresh it was crunchy! Secondly, the fat content of this fish is wonderful. It is very evenly distributed throughout the fish and usually has pretty silky texture. Lastly, the fish is the perfect size at 12lbs. I could comfortably fit 4 fish in the case at one time.
My team and I decided to age the fish for 1, 5, 14, 22, and 44 days. We set the dry ager to 0.8C and 85% R.H. The low temperature ensured the fish would not spoil due to temperature and the high relative humidity ensured we would not get fish jerky for the fish aged over 22 days. The DryAger also has a UVC filter that sanitizes all the air in the cabinet once every minute and has antibacterial walls. This would help prevent any outside bacterial or mold contamination.
Each fish was meticulously sujibiki knife scaled before getting tagged and hung in the case. Then we waited. Fish were then added to the case at intervals. Slowly, we could see the older fish start to dehydrate and the face get tight and the eyeballs recess into the skulls. The skin started to dry out and become hard like leather. At around 30 days, we started to get slight funky smell coming from the fish destin for 44 days. It was not a spoiled funk but a cheese cellar funk. As expected, there was not growth of mold on the fish. The UVC filter was doing its job.
After 44 days, I was finally time to cut the fish. I started with the oldest fish first. The skin was
very tough and difficult to cut through. The meat was very firm with a thick layer of oil. It had very appear funky smell to it. To be honest, I was scared to try it. After cutting and sitting out
for a minute, the funky smell slightly dissipated. I continued to cut the remaining fish. Now came the time to taste. This is what my team and I thought of each fish:
1 day: Clean, sweet, kombu
5 day: creme fraiche potato, flavor starts to bloom, super tender, earthy (mushroom)
22 day: Aged yellow cheddar, firm but tender
44 day: age brie, epoisse cheese, barn yard, tender, jerky, soft
Everyone's favorite was the fish dry aged 5 days. It was the perfect combination of flavor and texture. Buttery, melt in your mouth with a silky chew. The 22 day was the second favorite, followed by the 1 day and 44 day. The results were not a surprise to us and we were happy to find we could achieve tasty results of dry aging in under a weeks time. This is important because we are a high volume restaurant and would be unable to hold fish in the DryAger for an indefinite amount of time.
Unfortunately, for this tasting experiment, we missed a time gap between day 5 and 22. We did later trials and found that the point of diminishing return for king salmon is around 14-18 days. This is when the funky aged cheddar flavor start to develop.
Presently, we dry age our Big Glory Bay King salmon between 3 and 7 days. This is primarily due to our volume and space constraint. Luckily we are able to get the benefits of the dry ager within that time frame. Otherfish, however, need the long age. Next story will highlight the king of tuna:Western Atlantic Bluefin Tuna.