Barbecue : Ice, Relative Humidity & Electric Smokers

I loved the barbecue class on ChefSteps, it encouraged me to spend a bunch of money on a new electric smoker, and an Auber PID to maintain the dry bulb temperature of the smoker, and other gear so I can create the greatest ribs known to mankind. The class left me with some unanswered questions however, and I hope I can get some guidance how to proceed.

1) One of the common themes of all recipes in the class was to maintain the relative humidity with the use of ice. We are advised to change the ice when melted, which for me would be less than 30 mins per change which seems a bit over the top. Additionally all of the resources I read say that you should never open the door of an electric smoker when a PID is in use - not even to add more wood (4oz of wood blocks yield me around 5 hours of smoke). Is that bad guidance? Should I open the door every 30 mins to add more ice, or is the water left in the tray enough to maintain the humidity levels needed?

2) What is the best way to measure the relative humidity in a smoker? Right now I have one probe of the PID measuring the dry bulb temp of the chamber, the second PID probe is placed just under the skin of the meat. I also use a third probe attached to a Thermocouple embedded deep into the protein so I can measure the core temp. Should I consider the PID probe placed just under the skin of the meat to be the wet bulb temp, and then manually figure out the relative humidity - or is there a better way?

As an added bonus I present some food porn from my first smoke - hands down the best ribs I ever made, but I think there is still some room for improvement once I understand how to maintain and measure the relative humidity better.

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Comments

coryhansen78

Regarding 2) - my guess* is that the probe under the meat surface will be pretty close to the wet bulb, until the meat surface dries out - just like a temp probe in a wet sponge. If you were measuring both and comparing, both should rise to a point where they "stall" (i.e. now you are measuring actual wet bulb, I believe). When they dry out enough, the temp will rise noticeably (and you are no longer measuring wet bulb). If the two stall temps remain approximately equal throughout the smoking, I think the "meat-surface" method is valid.

You can use that wet bulb and the dry bulb temp to look up the relative humidity on a psychrometric chart (or use a calculator on the web). Here's a paper with a somewhat-empirical method that can be made spreadsheet-friendly if you are into that sort of thing. I spot checked a couple of temp combinations and it looks close enough for my purposes so far...

*I plan on testing this over the weekend with my first attempt at smoking pork ribs, using a dual channel temp probe (one for meat surface temp, the other for smoker air temp), and a third probe stuck into a wet sponge. That probe will be connected to a datalogger. I'll report back with the results.

Here's a reference article (look around on this site if you haven't seen it yet - pretty much mindblowing):
http://www.genuineideas.com/ArticlesIndex/chickenBreastHumidity.html

Hope that is helpful (and somewhat correct)!

coryhansen78

Ok, so regarding my above post, I did indeed check this yesterday and it performed about like I hoped it would. Despite my poor temp and humidity regulating skills--I need practice!

After sous-viding and then rubbing the ribs, I smoked them for 4 hours with the set-up I mentioned above. The meat surface temperature started out hot (from the sous vide step) and the sponge temp started out low (was wetted with room temp water -- oops). After that, they converged (the meat surface temp more-or-less dropped to the sponge temperature, which had by that time risen to the "correct" wet bulb temp in the grill), and after a couple hours the meat temp. started slowly ticking up.

In fact, even counting the higher start temp of the meat surface and the room temp water sponge, the percent error between the two probes averaged at 5.8% for the length of the smoke. For about 2 hours of the 4 hour smoke, it was around 2% error or less.

So, yeah, the "temperature probe below the meat surface" method worked as a good stand-in (at least for me in a 4 hour smoke) for wet bulb temperature. Although this was only a single trial, your mileage may vary, etc...

Besides the above, I learned a few things:

1. Yes, you can indeed get a smoke ring with pre sous-vide cooked meat.

2. It's really hard to get enough humidity (I used a 27" weber charcoal grill). Large blocks of ice worked for temp control, but I still needed more evaporation. I'm considering placing an immersion heater into the water pan below the meat (in addition to the ice block pan above the coals/wood, maybe hooked to a bang-bang controller?) next time to provide a little more evaporation.

3. The temperature probe stuck into the wet sponge stayed wet throughout the smoke. Maybe it wouldn't for longer smokes, but, I see no compelling reason not to combine sous-vide and smoking.

4. I kinda liked the flavor of the brined (Salt, Sugar, Insta-Cure #1) ribs that I did after this first batch. That might be heresy, not too sure? I did ribs two ways-- one the Chefsteps dry-style method with the data collection I mentioned above (very good, and I got the smoke ring on this set) and the other was a recipe from the Yucatán cookbook (by David Sterling, which is an awesome book, btw). These were the brined batch (I did have to adjust the curing salt amount as it was clearly written with Morton Tender Quick in mind). They were then marinated with mojo de ajo, cooked en sous vide, smoked and ultimately thrown in a pot of black beans with some black chile paste! I was up until midnight finishing--worth it.)

*In the interest of full disclosure, I've lived in Kansas City for the last 15 years, so, yes, I served the ribs with sauce (and I liked it).

Thanks to everyone at Chefsteps, I've learned a lot and made some pretty great food! I'm excited to continue cooking from the BBQ class!

ttpoker

Thank you Corey. I intend to perform your same research during my next smoke, which will be either a brisket or Chef Step's pastrami - both of which allow me to measure the difference between the core temp and the wetbulb temp. I am looking forward to this, not just because I will learn a new technique and be able to adjust humidity... I am more excited to eat the results ;-)

Interesting choice of brineing the ribs, not something I would have thought of doing. How did you like the Yucatán ribs vs the Chef Steps dry style? The Chef Steps method resulted in the best ribs I have ever had, I typically prefer a dry rub however (nothing wrong with a dry rub finished with a boss sauce KS style - I won't judge you, I like this too!)

I don't seem to have much problems keeping humidity in my electric smoker controlled by a PID, but I do question if I need to use ice cubes or if just water will do the trick. Typically I get to target dry bulb temp within 20 mins, the ice melts so quickly that it may be a wasted step - any comments from other readers would be appreciated!

coryhansen78

No prob, I had been thinking about these types of questions for the past few weeks too and my awesome wife recently got me a dual channel temperature probe for my b-day, so it worked out well!

The brine was per the recipe in the book. Yucatan cooking uses some really interesting techniques (such as the somewhat bizarre but delicious blackened chile paste that went into the beans), so I wanted to keep an open mind and follow the recipe pretty much exactly and do the brine and marinade (I did substitute the sous vide/smoke method found here for the smoke only method in the book-- I just love sous vide, that's all).

Regarding how the two recipes compared, It's a bit of an apples and oranges thing. My dry style ribs (with the Rib Rub from the website) weren't quite as juicy looking as yours-- I never got to the target humidity (between 30-40% was as high as I could get, using the meat surface temp as my wet bulb) but the taste was excellent - what BBQ ribs should taste like. My wife agreed. I used pecan, but might prefer a milder wood next time. This was my first time combining sous vide with a lengthy smoke, and I was pleased with the results. The rub was great too. Loved the mace.

The Yucatan ribs were a totally different flavor profile - they had a nice citrus tang (from the mojo - basically lime, grapefruit, orange juice emulsified into pureed roasted garlic and olive oil) and an overall Caribbean feel with that and the black pepper/allspice brine and rub. Almost jerk-like. Almost, but the mesquite brought it back to Mexico. Since I had troubles keeping the humidity where I wanted it to be on both attempts, I think the brine helped me a bit with this one. I do generally prefer brined to non-brined in a lot of preparations mostly from a flavor point-of-view (even with sous vide in many cases) though, but that's just me.

I'd say if you don't typically have problems with too high of temperatures within your smoker (and you shouldn't with the PID), using ice would indeed be a wasted step. You'll only have so much (well-controlled) heat energy to go around, so I'd rather have it vaporizing water than melting ice. But, since you have an electric smoker (lucky), you shouldn't have too much difficulty with humidity so i'm not really sure it matters.

SmallTed_806026

If you are first time smoking meat I suggest you to check Electric Smoke Guy