Smoking - Fixed time, what temperature?

[chef jimmyj]

I'd like to see your data...JJ

 

[chef jimmyj]

Speaking for myself I find nothing offensive in what you have said...As far as Pork Fat and rendering yes the fat begins to render at less than 100*F that is why it tastes so good when you eat Pork the Fat melts in your mouth...But...Think about cooking Bacon that is 50% Fat plus. While fat renders from the beginning it gets above 212*F before it looses the Water and even starts to render to the point it gets Crisp and Brown. So I can tell you from cooking many Butts to 205-210*F there will be plenty of Fat even in large enough layers, like Cap Fat, that they will need to be removed...JJ

 

[so ms smoker]

   Please post the controlled time and temp tests! I'm sure we would all be interested in it.

Mike

 

[banjo]

Guys,

I just clicked in the 'attachment' button, and it says that I don't have permissions to create attachments.  So I'm going to have to post it to my blog.  Will update this thread when it's up.

Meanwhile, I'm going to Costco later to pick up the meat and get it going under the 300 dF cooking temperature.  

Thanks again for all the great insight and comments.  I'm hoping it turns out wonderful for us today, and will create a new smoker enthusiast of my friend and his wife.

And...I hope this turns out better Q then my method, so I can cut the time down that's involved!

 

[banjo]

Hey - since we're talking about data, here's a circuit I designed and built that works with Arduinos for obtaining data from (up to) 8 channels of thermocouple inputs (the two green strips on the right).  It has a date chip (for logging the time and date), a battery backup (for the date), and it stores the data on an SD card (bottom left - the PNY is the SD card inserted.)  It plugs into an Arduino (the two black strips at the top and the two at the bottom).  It also has a plug in display (not shown in this - the display isn't my design, and was purchased.)

I'm still working on the software for it, as I want to also add the ability to control a servo to open/close an intake valve for natural draft damper control.  Using the Arduino, it can live-stream the data to a computer. 

my circuit board and design.jpg

• banjo
• Jul 29, 2012

 

[banjo]

I thought it would be a good idea to post the data summary here, then link to the actual data itself.  However, I haven't been able to find a way (yet) to insert a spreadsheet into my blog, so all I can do at the present is provide a summary of the data.  If I can find a way to insert the spreadsheet into my blog, I'll update this thread.

This data was obtained using thermocouples using a circuit of my design.  It was calibrated against a calibrated thermometer.

The purpose of the test was to allow me to obtain some data that would allow me to select a desired time (just like my need for 6 hours today!), and then determine what the temperature should be held at for the meat's internal temperature.  The data was obtained from a thermocouple inserted into the middle of a controlled cross-section of pork shoulder (boneless).  It was then cooked in a Souse Vide machine (in a bag to keep out the water), at a controlled temperature (+/- 2 degrees) until the meat (in my subjective judgement) was pullable.

The test was to determine the length of time necessary to produce pullable meat if  the internal temperature of the meat was held at a controlled constant temperature.  The time to cook at temperature is started when the meat reaches the stated test temperature.  It does not include the time to bring the meat up to that controlled temperature. That's very important to understand.  Since bigger pieces of meat require longer to come up to temperature, that time would vary depending on the size and shape of your meat.  However, once it's up to the controlled temperature, the question was - how long does it need to remain at this temperature before it becomes pullable (and that's subjective based on what I consider pullable).

So here is the summary of the data.  

Controlled Temperature                Time at Temperature to become pullable

145 dF                                        41 hours

155 dF                                        31 hours

165 dF                                        14.5 hours

175 dF                                        bad data - temperature probe pulled out

185 dF                                        5.25 hours

195 dF                                        2 hours

I did a scatter-plot of the times, and they are predictable.  

Thanks for the interest, insight and comments!

 

[daveomak]

So here is the summary of the data.  

Controlled Temperature                 Time at Temperature to become pullable

145 dF                                        41 hours

155 dF                                        31 hours

165 dF                                        14.5 hours

175 dF                                        bad data - temperature probe pulled out

185 dF                                        5.25 hours

195 dF                                        2 hours

Banjo, morning....... If I understand your chart,  You held the meat at 195 dF for 2 hours and it was pullable ???   That makes sense to me...  I held a brisket at 180 overnight and it was pullable....  Good and moist too....  Dave

 

[banjo]

DaveOmak,

Yes, that is correct.

 

[banjo]

Guys, if you want the actual data, send me a message with your email address and I'll send the spreadsheet to you.  Doesn't look like I can post it otherwise.  Sorry - thought that would be easy to do!

 

[banjo]

Guys, this is looking like a disaster.

I'm smelling burnt oil.  This is from the catch basin that is under the meat, and is exposed to the 300 dF temperature.  In looking up the smoke temperature for pork, it shows it being between 250 and 425 (wiki).  So my oil from the fat being rendered out of the meat is above the smoke point for the oil, and I'm smelling it.  

I don't see any way this smell isn't coating the meat.

I hope I haven't ruined our meat and wasted the day.

 

[chef jimmyj]

How did it come out? This is a little late but there is no reason you can't put some water in the Drip Pan to keep the grease from burning...JJ

 

[banjo]

Chef JimmyJ, just call me Simple.  Didn't think of that at all, of course, at 300 it would evaporate pretty fast!

Anyway, it had a nice flavor, so the overheated oil didn't appear to ruin the meat.

However, a considerable amount of the fat had rendered out, so it was much more dry than I am used to. 

However, given the time constraints, I consider it 'good stuff' and we all enjoyed it, and that's all that really matters!

I'm suspecting the difference here is in the smokers between what I'm using and maybe what others are using.  I don't have an offset at the moment, this is a vertical smoker, so the heat source (charcoal) was about 6 inches under the drip pan.  I put something between the drip pan and the charcoal to block the infrared, but it still got too hot.

I'm going to be modifying this smoker when the weather cools down, to move the combustion area outside the smoker, so that will help with this problem, as well as improve my damper control and ability to add charcoal without having to open up the cabinet.

I really appreciate all your suggestions and contributions you've made to this forum.  Have read quite a few of them.

Banjo

 

[chef jimmyj]

Glad it worked out and thanks for the kind words. I am going to save your chart for future ref. I have had Butts stall for extended time above 190*. Based on your data I can guage the Time to Tenderness and not sweat the final temp...JJ

 

[jarjarchef]

Very interesting info. I'll PM you for the spreadsheet. I like numbers :biggrin:!

On the grease burning part. I know this will sound crazy, but we use this method on our gas grills at work. We line the drip pans with foil and then spread several boxes of baking soda in the drip pans. No flare ups and have not noticed any flavor added to the product.