Wet brine for smoked salmon...is this normal?

So I'm trying a recipe for smoked salmon that a friend passed on to me. It's a wet brine, which I've never tried before.
The recipe calls for 36 hours in the brine. I'm at 12 hours and the pieces of fish are not very firm yet, a little I suppose but not much.

With a dry brine - just salt and brown sugar - the fish is very firm after an overnight soak.

So is this normal? I suppose the longer brining timine - 36 hours - is part of the equation?
How firm should I expect wet-brined salmon to be after 24 or 36 hours?

Any tips would be great. I'm just hoping I'm not bungling this!
Thanks,
Andrew

Not sure you're looking for firm while wet brining.  I only soak overnight then create pellicle in open air in fridge or with fan on in smoker.  Also depends on the salt content of your brine...I prefer a moist finished product vs. a jerky like result but that is me.  Pull some out and try a few different time references and see what you like best.  My fear is always oversalting....inspiring nonetheless,  I better get smokin' mine as well...

If a brine recipe doesn't contain very much salt, you'll need to leave the fish in the brine for a long time in order to reach a desirable level of saltiness.  If a brine recipe has a higher concentration of salt, you may need to leave the fish in the brine for only a couple of hours.  The length of time you need to leave the fish in the brine also depends on the thickness of the fillets or pieces of fillets which you are smoking. The soaking time called for by various brine recipes varies wildly.  You usually need to go through a trial and error process when learning how to use a wet brine recipe.  Start by leaving the fish in the brine for the length of time specified in the recipe, and take notes about the length of time and the size and species of the fish you brined.  If the smoked fish is too salty, reduce the brining time next time you use the recipe.  If the smoked fish is too bland, increase the brining time next time you use the recipe.

To reduce this trial and error process, I standardize the salt content of all of my brine recipes at 60 degrees Salometer. This is a moderately concentrated brine which produces pretty short brining times.  Here are examples of the brining times which I use for several of my favorite recipes: 11"-12" kokanee fillets, 1.75 hours; 15"-18" kokanee fillets, 2.5 hours; 20"-24" lake trout fillets cut into 3" pieces, 3.25 hours; 18"-21" lake whitefish, thick part of fillets 3 hours, thin rib meat from fillets 1.5 hours.  I keep careful notes on the results of each batch of smoked fish, and adjust these instructions.  My note taking allows me to get consistently good results when I smoke fish.

Adjusting the quantity of ingredients in a brine recipe to produce more or less brine than the original recipe can be a hassle.  For example, how many tablespoons are there in a cup? if you screw up your conversion or your math, you can end up with a lousy batch of smoked fish.  To make it easy to adjust the quantity of ingredients in my brine recipes, I put them on Excel spreadsheets.  All I have to do is enter the number of cups of brine that I want, say 5 cups, and hit tab, and all of the quantities in the recipe automatically adjust.

Recipes which specify dry ingredients by weight will produce more consistent results than recipes which specify dry ingredients by volume, because the density of dry ingredients varies quite a bit.  For example, a cup of table salt weighs more than a cup of kosher salt, and a cup of compacted brown sugar weighs more than a cup of loose brown sugar. I convert all of the dry ingredient quantities in the brine recipes I use to weights.

I only use wet brine recipes, because they produce more consistent results than dry brine recipes.

Here's a couple pictures of fish being brined in ziplock bags.  I periodically massage and flip over the bags to expose the fillets evenly to the brine.

That's good stuff, thanks for posting...

What pmmpete said!
I also only use a wet brine. I did go through a trial and error process. Take notes. It’s important to just change one variable at a time, in this case, time in brine.

After this round, if you’re happy, great! Now you can tinker with the small stuff like heat (cayenne) or brush on items like maple glaze.

If too salty, reduce time in brine next time but keep everything the same - same size cuts, same time to form pellicle (use the sticky fingers test - you’ll get a sense of the right kind of sticky feeling on the fillets).

After you get the taste right, you can tinker with temps/time (next variables to tackle) and smoke time (additional variable). Definitely a process but once you find something you like, it is repeatable and oh so yummy. Good luck!

Wet or dry the amount of time you brine for is determined by how much salt there is in the brine and how salty you want the finished smoked fish to be.

36 hour brine will have lower salt content and take more time to absorb in to the fish.

Longer brine times will give you more of a margin of error--if your brine time is 36 hours and you leave it in for 37 it will be fine, where as if your brine time is 15minutes and you leave it in for 20minutes you might be too long.

Something to always be aware is what type of salt you use.  A cup of salt can vary a lot by weight depending on the type.  Sometimes even 2x the weight.  It's best when you are recording your brines to use weight instead of volume measurements.

I tend to go for a shorter brine time (so high salt content in brine) as I've been following more industrial guidelines and thats what they do.  But in the end it doesn't matter, long or slow, as long as you end up where you want to end up.

For smoked salmon that I will can in a pressure canner,  I use a simple dry brine for 40 minutes (250g salt, 150g brown sugar, fridge, rinse after 40min).  But on other fish I have used wet brines of 70 or 80 degree strength for around 8-20 minutes depending on their size.  I use this on mackerel, herring, and rockfish/lingcod.

https://seafoodacademy.org/brining-activity.php

i do 12h in Kikkomans Teryaki for basically all my fish and it works very well.  Pictured are salmon and tuna bellies