# Thoughts on automating the salmon smoking process



## wrybread (Sep 23, 2021)

Thanks massively to everyone who helped me dial in the "thin blue smoke" on my smoker, especially 

 cmayna
 and 

 tallbm
. I learned a ton. I cringe when I look at my old pics of crazy white smoke ruining my fish.

Now I'm thinking about somewhat automating the smoking process, because I caught a ton of salmon this year and I'd love to be able to bang out small batches without having to hover around my smoker all day. There's nothing like salmon right out of the smoker, nice and warm,  I vote better even than cookies, ha.

I read a post from 

 tallbm
 about his automation so I know I'm not the only one interested in this.

Anyway here's my thoughts, suggestions invited:

I'm a big fan of Arduinos, which for people who don't know are simple tiny and cheap programmable computers that are ideally suited to controlling the heat on a smoker. But actually I use a variant called an ESP32 since it's even smaller and cheaper (around $8 usually) but most importantly has built-in bluetooth and wifi.

They're really easy to control from a phone or tablet, either via bluetooth or wifi.

That makes it possible to easily monitor and control the smoker over the internet, including getting alerts when the temperature has gone up too high (the wood has flamed up) and when the   wood has extinguished and I'm not smoking anymore.

Anyway I was wondering what ideal sequence people here would suggest for low temp smoking salmon? I know it varies a bit with the thickness of the meat and amount of brining time and various other factors, but as a starting point I'm thinking something like:

- 1 hour of 110 degrees
- 2 hours of 120 degrees
- 2 hours of 130
- 30 minutes of 140?

I'm thinking that should be flexible in the phone interface, so can have X minutes of Y degrees, followed by X2 minutes of Y2 degrees, etc. Maybe the interface looks like this:

___ minutes off
___ minutes 100
___ minutes 110
___ minutes 120
___ minutes 130
___ minutes 140
alarm

And the user can drag those into whatever order they want, fill in the number of minutes for each, then press start. And looking at the interface during smoking can see how many minutes it's had and how much longer it has to go.

Another thing I'd like it to do is certain watchdog functions. For example my Amaze-N maze smoker still extinguishes, and it's totally possible that that's user error and I'm not giving it enough time to light, but it means I have to check on the smoker pretty often. So I was thinking it would be nice to have a smoke detector. I found a few options, this being the current top contender:

Waveshare Dust Detector Module with Sharp GP2Y1010AU0F

Pros:
- can measure PM2.5, which is (as I understand it) the main component in an "air quality index" (AQI) gizmo. So maybe it could tell me not only whether the smoke source is on or off but also whether I'm getting "thin blue smoke"...
- it can be powered by 3.3 volts, which is what the ESP32 uses (regular Arduinos use 5v).

Cons:
- the mechanism might be especially delicate and get fouled if installed directly in the smoke stream, so will probably need to install it externally.
- is $17

There's also the EIEChip Smoke Sensor Modules aka MQ-2 etc.

Pros:
- cost about $2 and are ubiquitous
- there's a bunch of them each specialized for different gasses. One might be ideal for our purposes.

Cons:
- I don't think can be powered by 3.3v, needs 5v
- lots of complaints of poor calibration, but  might be accurate enough for an "is the smoke on?" type measurement

Then just a temprature probe (can be multiple, including ones that go inside the meat) and a relay that works with 3.3v (that relay is enough power for my 600 watts/5 amps of power heating element but of course that's a factor, can always swap the relay or have the relay trip a secondary relay).

I'd probably skip having a local display and interface, using only my phone to check on the temperature, but could easily add one. Or just use one of my ol reliable temperature probes to rule out looking at old data and things like that.

Thoughts? Anything I'm obviously missing? Anything you'd add to make it the perfect salmon smoking automator?


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## thirdeye (Sep 23, 2021)

You are sketching together some amazing ideas for this 'automator' project!   I'm assuming you are a young man?  Just for grins, do an internet search for a gentleman named 'Shotgun Fred' Pirkle who was the founder of BBQ Guru.  He was a rare combination of engineer, inventor, designer, patent holder and BBQ man.  I don't know which one he loved more (I suspect it was BBQ), but the best description I've read was from his obituary.  It was simply....  "_He’s just a gadgeteer".  _I have one of his early analog forced draft controllers, and in those days it was not uncommon to call the company with a question and visit with Fred or his partner BBQ Bob.



wrybread said:


> Anyway I was wondering what ideal sequence people here would suggest for low temp smoking salmon? I know it varies a bit with the thickness of the meat and amount of brining time and various other factors, but as a starting point I'm thinking something like:





wrybread said:


> Thoughts? Anything I'm obviously missing? Anything you'd add to make it the perfect salmon smoking automator?



About all I can share is my experience with smoking fish, hopefully something will stand out and assist you in some way.  I've smoked fish my entire life, but only in the last 25 or 30 years have I really refined my process which is dry cure then cool/warm smoke/hot finish.  I only smoke trout, steelhead, salmon and on occasion ahi tuna.  My primary equipment are the Little Chief and Big Chief box smokers. I got my first one in 1973 and have worn a couple of them out.   The smoke generator is a 'hot plate' design, meant to burn wood chips.... but once flavor pellets came on the scene I began using them. The 'Chief' line of smokers have NO controls, they are on or off.  Blocking the lid open or unplugging it are your only adjustments.   I use a handheld instant read mini thermocouple thermometer and monitor the fillets on the top rack.  Then after 3 or so hours I might lift out the frame and racks to spot check other fillets.






Don't laugh too loudly, but the first (and only) 'automated' improvement I made was using one of those plug-in timers used to control lights or your coffee pot.  It had a plastic wheel with plastic pins that were place settings for ON and OFF.  Mine had holes that represented 15 minutes.  Using the pins, I could cycle the smoker on and off for hours to maintain the temps I wanted.  This was more convenient than unplugging the smoker every 30 minutes to let it cool off.  'Chief's' run between 80° and 170° depending on weather conditions.  I have a dial stem thermometer I will use to monitor smoker temp, but usually just feeling the box is a good indicator.

* I think you are right, certain variables will be one of your challenges.....* I have come to the conclusion that smoking fish is in many ways harder than smoking other meats because of the number of variables.  When you catch your own, the meat must be cared for immediately.  When buying fish you have to select the fillets very carefully.  Time of the year, species and the type of waters (lake, stream or river) are also important.  Then comes thickness, fat percentage, skin-on or skin-off.   Then comes the smoking process..., I use all my senses.  I smell the smoke, watch the color develop, ease the smoker temp and internal temperature up over 3 to 6 hours.  My goal is developing color, flavor and doneness without drying or forcing an excess of albumen out of the flesh.  The last variable is outside temperature, two batches of my fish will almost never follow the same time table.

I guess the proof is in the pudding, here are the kind of results I shoot for with my 'hands-on' approach.  This is the first smoked fish photograph I posted on the internet in about 2005.  I believe it's Sockeye, and in those days I used mostly cherry.  The topping is red and green peppercorns which I soaked in hot water for an hour, then added a few hours before smoking. 





This is Rainbow trout from my home waters in the Rockies.  Maybe a 3# fish.





This is Atlantic Salmon.  As you can see by now I like peppered fish. I'm using a lighter wood smoke, probably a blend of apple and cherry.





This is Steelhead.  I think it's my favorite for flavor and fat ratio.





I smoke more fish in the late fall before the lakes freeze, and always a lot for holiday gifting.  This is a side of Steelhead.  I package them on smoking planks for transport, and it's a built in cutting board.





Lastly sizing is important.  This is Steelhead that I cut down based on thickness. I stagger the location of thick and thin pieces in the smoker so they cook more evenly.


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## olaf (Sep 23, 2021)

I like what your trying to do I was trying that exact setup but just didn't have the patience to learn to write an app so I kept going backwards in technology about 30 years. The relays will be an issue and will need to be about double the current  rating of the heaters. Good luck


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## tallbm (Sep 23, 2021)

wrybread said:


> Thanks massively to everyone who helped me dial in the "thin blue smoke" on my smoker, especially
> 
> cmayna
> and
> ...



Interesting project!

I think you have the controller and the steps down with no issue. Writing the App software may be the biggest problem there lol.

I'm curious about the smoke detection.
I wonder if you may be better off detecting a range of heat within your mailbox mod and if it falls below a certain temp then you know the cherries are low and minimal to no smoke is being produced. Measuring smoke is a tricky business.

The other idea I had is if you wanted to do a laser type sensor (just brainstorming here) that is blocked or interrupted by smoke as it is being produced and flowing through the tube of your mailbox mod. Should the laser actually not be interrupted for lets say a straight 1 minute period then alert that the smoke is out.

A smoke sensor could maybe be used to do the same but I fear that since they meant to detect smoke and not the absence of smoke they may fowl or wear out or just not be adequate.

Yeah its TBS but ONLY when leaving your smoker. You will still see visible amounts of smoke as it builds up in your smoker. This makes me think you can do some sort of photelectric cell/laser sensor in the duct of your mailbox mod setup and when the laser is not dispersed enough then it alerts you that smoke generation is failing.

I hope this gives some food for thought :D


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## wrybread (Sep 24, 2021)

thirdeye said:


> I'm assuming you are a young man?



A young man of 51! Still stupid enough to waste tons of time on silly projects like this and may that never change, ha.



thirdeye said:


> The smoke generator [in a Big Chief] is a 'hot plate' design, meant to burn wood chips...



That's what I use in my MasterBuilt smoker by the way, assuming you're using the stock heating element in your Big Chief. When I first picked up my MasterBuilt after a couple years of using a Big Chief I hated the thing and was going to throw it away because the heating element was so powerful that by the time it was making smoke it was something like 180 degrees inside the smoker. I might be exaggerating, it was a long time ago, but it was definitely too hot to smoke salmon the way I like to do it (Big Chief style, down around 130 to 140). So I tranpslanted the heating element from my old decrepit Big Chief and use it for the heat source, though the smoke now comes from an Amaze-N maze pellet smoker in something like the "mailbox mod" (in my case one of those little BBQ's instead of a mailbox).










thirdeye said:


> I use a handheld instant read mini thermocouple thermometer and monitor the fillets on the top rack. Then after 3 or so hours I might lift out the frame and racks to spot check other fillets. Using the pins, I could cycle the smoker on and off for hours to maintain the temps I wanted.



Great idea.



thirdeye said:


> I use all my senses. I smell the smoke, watch the color develop, ease the smoker temp and internal temperature up over 3 to 6 hours
> 
> My goal is developing color, flavor and doneness without drying or forcing an excess of albumen out of the flesh. The last variable is outside temperature, two batches of my fish will almost never follow the same time table.



Good advice. So do you put a probe inside some salmon to test for internal temp? Any words of wisdom about what internal temps you like to see at what points in the smoking process?



olaf said:


> I like what your trying to do I was trying that exact setup but just didn't have the patience to learn to write an app so I kept going backwards in technology about 30 years. The relays will be an issue and will need to be about double the current rating of the heaters. Good luck



In theory this remote controllable relay board uses the same cheap 10 amp relays I've been using for years, but with Chinese crapware it's always worth watching, ha. At least if they explode they're in an area where they can't do me any harm, ha.



tallbm said:


> Writing the App software may be the biggest problem there lol.



As always! Luckily I don't have to start from scratch so I can make something barebones functional without too much work. And with the ESP32, the gizmo I like to use, there's always the option of a web interface, which are easy enough and I've made a bunch of them. That's usually the route I go for this kind of project though there's always the Cadillac route of making an Ionic app that cross compiles to iOS and Android, and interfaces via Bluetooth... But I probably won't do that, I'll probably just make a simple web interface.



tallbm said:


> The other idea I had is if you wanted to do a laser type sensor (just brainstorming here) that is blocked or interrupted by smoke as it is being produced and flowing through the tube of your mailbox mod. Should the laser actually not be interrupted for lets say a straight 1 minute period then alert that the smoke is out.



Good idea! And everything is of course better with lasers.

You're probably correct and wise in suggesting that temperature be the indicator for the smoke generator functioning. But those smoke sensors are cheap enough and I'm curious enough to want to play with them a bit, so I ordered both the fancy AQI indicator and the cheapie gas detection sensors. Those MQ-* sensors are like $2 each so even if one fails every 10 batches it's probably fine. But I guess I could see that getting old.

Here's what I'm thinking for a simple app interface:







Press the "+" button at top of the schedule area to add a new item, set the type of item ("___ minutes at ____ degrees"),  then move it around with the "up arrow" buttons on the right. The graph on the bottom, which would show the schedule (the rectangles) versus the actual temps, is admittedly ambitious, ha. And not really necessary. The biggies are:

- a way to create a schedule and upload it to the brain
- a way to see where we are in the schedule
- display current temperature and smoke quality
- some way to set and send alerts for: if the smoke generator extinguishes, or the temp goes too high (there's a fire), or if the brain stops updating

A nice v2 feature would be to have each batch assigned a unique number and later be able to look up the cooking/smoking times of that batch to repeat it. 

Anyway thanks for letting me think out loud, and please let me know any other ideas if anything strikes you.


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## cmayna (Sep 24, 2021)

Guess I'm a little confused about the definition of "Automating the salmon smoking process".     If you use a controller like a Auber, you are automating a programmed amount of heat over a programmed amount of time.     For my Salmon the time spent smoking will vary depending on the thickness of the meat.  

The only thing not so programmable or automated for me is the amount of smoke.  Yes, I am constantly looking at how much smoke is being generated from the mailbox.  

Think I'm missing something here.  "what else is new, says the wife"


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## wrybread (Sep 24, 2021)

> Guess I'm a little confused about the definition of "Automating the salmon smoking process". If you use a controller like a Auber, you are automating a programmed amount of heat over a programmed amount of time. For my Salmon the time spent smoking will vary depending on the thickness of the meat.



Interesting! I didn't know that the Auber is programmable like that. Looking at it's specs I see that it has a lot of features I'm describing.

But it doesn't have a super crucial feature for my purposes: the ability to alert me if the smoker extinguishes. Ditto being able to alert me if the temp goes above X degrees, meaning that there's a fire. 

I guess I could just make a "smoke source watchdog" gizmo, which would probably take all of an hour and pick up the Auber, but spending about $40 instead of $225 is a nice bonus and I like the flexibility of rolling my own. Ultimately this is all pretty simple stuff.

And out of curiosity, do you find yourself repeating the same parameters each time you smoke or does it vary widely?


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## wrybread (Sep 24, 2021)

And ha I knew the name Auber sounded familiar, I used to have their temp controller on my old espresso maker:


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## cmayna (Sep 24, 2021)

I use the same parameters which I have set up for the Auber.  The only difference is when doing larger pieces of fish, such as filets,  I extend the smoking time for another hour plus.  Otherwise it is pretty automated.  

I have a video camera with an app, so I can watch the smoke without having to be next to the smoker.


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## wrybread (Sep 24, 2021)

Good idea about the video camera. 

Do you usually supply smoke during the whole time, or only part of the "cook" time?

And any idea what your typical cook time sequence looks like?


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## cmayna (Sep 24, 2021)

Yes if I have a small amount of smoke going, it will continue to smoke for the whole session.  If though I'm having a large amount of smoke going, I will sometimes pull the pellet smoker out of the mailbox maybe during the last hour plus.

Assuming the ambient temp during spring, summer or fall, my typical sequence is:

125* for an hour
135* for an hour
140* for an hour +

Bigger pieces need more time at these lower temps.  My Auber has 6 timed sequences which are all programmable.


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## thirdeye (Sep 24, 2021)

wrybread said:


> Good advice. So do you put a probe inside some salmon to test for internal temp? Any words of wisdom about what internal temps you like to see at what points in the smoking process?


No, not a permanent probe during the smoking.  I have a fine tip TC on a hand held thermometer and I spot check the top rack.  This probe is very fast and so delicate I can temp a shrimp when pan searing, or temp a burger from the side.   Of course, this probe is universal, so I guess it could be rigged as a permanent one.


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## tallbm (Sep 24, 2021)

wrybread said:


> A young man of 51! Still stupid enough to waste tons of time on silly projects like this and may that never change, ha.
> 
> 
> 
> ...



Yeah seems super cool with lots of tinkering haha :D

I went a lazy yet super practical way of alerting for smoker off or overheat. I use the Inkbird 4 probe IRF-4S remote thermometer. 4 probes. Has high/low alarm.
Why did i go this route? For multiple racks and pieces of meat to measure temp along.
I run a ton of probes for situations where I have like 6 racks of ribs, 4 pork butts, etc. all going at once.  I must  measure each rack level and a  piece of meat or 2 on each rack so I need more probes and a couple of extra remote thermometers do the trick just well, plus I can use them inside in the oven :D


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