Humidity and Smoking Jerky

Discussion in 'Food Safety' started by wpg3ut, Oct 17, 2016.

  1. wpg3ut

    wpg3ut Newbie

    What is the general consensus on adding humidity while  smoking jerky? I have read that to aid in killing pathogens  on the surface  you should add a shallow bowl of water to smoker and that you need to have a 90% relative humidity ratio the entire cook time. Any thoughts on this?  Is a big bowl of water the best/ easiest way to accomplish this?
  2. dirtsailor2003

    dirtsailor2003 Smoking Guru OTBS Member

    I use a dry pit for everything I smoke.
  3. chef jimmyj

    chef jimmyj Smoking Guru Staff Member Moderator Group Lead OTBS Member

    The goal is to dry it asap. Bacteria can't survive without water. Post your source, 90% humidity? With Cure? What temp? I guess there could be a process where humidity is needed but not Homemade Jerky...JJ
  4. wpg3ut

    wpg3ut Newbie

  5. Just at a quick scan, this process takes the product quickly to the target temp for the recommended time to kill pathogens then the drying process begins and humidity is removed. When done this way the addition of moisture to maintain humidity until pathogen reduction makes sense. I do not see this process using cure which I would think would classify as an intervention. This is along the same lines as 40 to 140 in under 4 hours.
  6. chef jimmyj

    chef jimmyj Smoking Guru Staff Member Moderator Group Lead OTBS Member

    As I suspected...The 90%RH becomes critical at the lower temp processing, IT of 130 to 145°F, of Commercial Jerky production.

    NOTE: Appendix A is the standard Pasteurization chart with processing time at various temps.

    The humidity options in Appendix A that are applicable to jerky processing are: o Heating jerky to a minimum internal temperature of 145 °F (62.8 °C) in an oven maintained at any temperature if the relative humidity of the oven is maintained either by continuously introducing steam for 50 percent of the cooking time or by use of a sealed oven for over 50 percent of the cooking time, or if the relative humidity of the oven is maintained at 90 percent or above for at least 25 percent of the total cooking time but in no case less than 1 hour; or o Heating jerky in an oven maintained at any temperature that will satisfy the internal temperature and time combinations from the chart provided in 19 Appendix A if the relative humidity of the oven is maintained at 90 percent or above for at least 25 percent of the total cooking time but in no case less than 1 hour. The relative humidity may be achieved by use of steam injection or sealed ovens capable of producing and maintaining the required relative humidity. 

    While 145 may be common for Commercial Production it would require specialized control and monitoring. Not something one should attempt without more detailed training . Kind of like adding Cure #1 to make Kielbasa verses having the skill and specialized equipment to ferment and Dry Cure an Italian Salami for several months.

    In general, SMF and the most common recipes for Home Production includes heating to an IT of 165°F during the beginning of smoking or before dehydrating at 130 to 140. Below is an excerpt from the FSIS/USDA Fact Sheet on Homemade Jerky Safety with no mention of maintaining any % RH. Heating to 165 at the start kills all active bacteria in seconds so there is no time for the bacteria to become heat resistant as it could at lower temps.

    Why is temperature important when making jerky?  Illnesses due to Salmonella  and E. coli  O157:H7 from homemade jerky raise questions about the safety of traditional drying methods for making beef and venison jerky. The USDA Meat and Poultry Hotline's current recommendation for making jerky safely is to heat meat to 160 °F and poultry to 165 °F before the dehydrating process. This step assures that any bacteria present will be destroyed by wet heat. But most dehydrator instructions do not include this step, and a dehydrator may not reach temperatures high enough to heat meat to 160 °F or 165 °F.

    After heating to 160 °F or 165 °F, maintaining a constant dehydrator temperature of 130 to 140 °F during the drying process is important because:
    • the process must be fast enough to dry food before it spoils; and
    • it must remove enough water that microorganisms are unable to grow.
    Why is it a food safety concern to dry meat without first heating it to 160 °F?
    The danger in dehydrating meat and poultry without cooking it to a safe temperature first is that the appliance will not heat the meat to 160 °F and poultry to 165 °F — temperatures at which bacteria are destroyed — before the dehydrating process. After drying, bacteria become much more heat resistant.

    Within a dehydrator or low-temperature oven, evaporating moisture absorbs most of the heat. Thus, the meat itself does not begin to rise in temperature until most of the moisture has evaporated. Therefore, when the dried meat temperature finally begins to rise, the bacteria have become more heat resistant and are more likely to survive. If these surviving bacteria are pathogenic, they can cause foodborne illness to those consuming the jerky.

    I hope this addresses your concerns...JJ
    Last edited: Oct 19, 2016
    76lowandslow likes this.
  7. wpg3ut

    wpg3ut Newbie

    JJ Thanks again for the in-depth reply. Very helpful. So I make jerky in a fairly large offset smoker. I usually get temp up to 190* with just charcoal and start jerky at that temperature or at least 180  for 2 hours.  its hard to insert probe in 1/4"  slices of jerky  so I hang probe in center of  smoker at same level of jerky  to get accurate reading of internal temp of smoker.  I cook for two hours and then add smoke for two hours keeping temperature always above 170*. So these temps clearly are above the 40/140/4 rule so I assume I should be in good shape. As we have  previously discussed I am trying to stay away from cures while maintaining safe preparation procedures.

     Thanks again JJ for all the insight. and just to be clear you would not introduce humidity with the above described smoke procedures?

      Thanks again wpg3ut
  8. sigmo

    sigmo Smoking Fanatic

    JJ is the expert, but from my reading of that and other documents, I gather that the important point is to get the meat up to an IT of 165° F BEFORE it can dry out, even on the surface.

    And as he pointed out, since meat that is wet/moist on the outside doesn't tend to get up to the smoker's air temperature (because the wet surfaces are being cooled by evaporative cooling), you really have a dilemma when making jerky.

    On the one hand, you're trying to dry the meat.  On the other hand, if the meat dries before it gets to a high enough temperature to kill the bacteria, then a lot of bacteria species will go into a "self protection" mode, and create spores or some more hardy form that can withstand even higher temperatures!

    So the recommendations are to make sure to get the meat up to 165° while it is still completely wet.  That's where the steam injection, etc., comes into play for people/companies who have that kind of equipment.

    For me, doing this at home, I can't inject steam into my smoker.  So I wouldn't feel comfortable running jerky in my smoker without first using some other method to get the meat all up to 165° while it's wet.

    I HAVE made jerky without doing that, before I read that document!  And I've gotten away with it.  But I always froze it for long-term storage and then kept it in the fridge for short-term storage, only having it at room temperature for fairly short times (less than a day).  I also used Cure (Nitrite) when marinading it.  So I had the insurance of that germicidal treatment.

    Now, after the marination time in the fridge, I plan to put the meat and marinade into a large pot and heat it until the whole "stew" is up to 165°, and then drain it and hang it for the smoker.  That way, I will know that it's been pasteurized, while wet, before I even begin to dry it.

    I'll feel safer having done that.  I just hope it doesn't wreck the jerky.  :)

    Is that going overboard?
  9. nepas

    nepas Smoking Guru Staff Member Moderator Group Lead OTBS Member SMF Premier Member


    I been making jerky for 34 years wrong.
  10. chef jimmyj

    chef jimmyj Smoking Guru Staff Member Moderator Group Lead OTBS Member

    It is important to understand that the Commercial Procedure is necessary to ABSOLUTELY cover the companies A$$ where some portion of what, a 10' X 20' Smoke room or 100' tunnel smoke oven may be a few degrees low or some step in their HACCP Plan for handling was not met. Or there was some Human Error or beef quality issues along the way. 

    At home a 1/4" piece of meat in a 160°F home smoker or oven will be up to temp LOOONG before any spores can form OR as with the lower Commercial 130-140 temp, any bacteria can become heat resistant. Short of Ground Jerky, the bacteria is Only on the surface and again at 160 or higher is killed quickly, less than an hour. Is Cure extra insurance? Sure. If smoking 190-200°F or Boiling the Meat first makes you feel better and you are happy with the result, Have at it.

    As NEPAS alludes to, Jerky has been made without 90% Humidity and without much Heat for Hundreds of years. Biltong is made with salt only and dried in the sun or in a Cardboard Box with a 100W Light Bulb. Hawaiian Pipikalua Beef is also salt only and also laid out in the Sun to dry. Per the USDA...Get good quality fresh meat, handle it safely throughout processing, start smoking at 160-165 for the first hour or so and then maintain 130-140 until dry, and you will have nothing to worry about...JJ 
  11. sigmo

    sigmo Smoking Fanatic

    Well, that's what I've always done, but I have always used nitrite as most of the recipes I find on here include.  And I've never gotten sick or made anyone sick.

    But since I've done the smoking/drying of the jerky at a smoker temperature of 160 to 170, I really can't say for sure what surface temperature was truly achieved before it dried enough for bacteria to start getting hardy on me.

    I will say that the last batch I made (which I am still enjoying) probably DID get to a surface temp of 160 or so well before it dried because I just wasn't getting very good draft through the smoker at all.  In fact, in frustration, I eventually put a small fan at the air inlet to force air through, and then the jerky actually dried in a reasonable period of time.  So I KNOW that batch was plenty wet for hours in that 160 to 170 degree smoker.  So maybe that's something that we should actually shoot for.

    Start off with the smoker at the desired temperature, but restrict the airflow through it for the first hour or two to get that "moist cooking" action.  Then hook up the fan or open the vents or whatever to get good dehydration.

    Also, wasn't one of the points about the guidelines in that document that the resulting jerky was supposed to be "shelf stable" for some very long time with no refrigeration required?  I can imagine commercial jerky hanging on a rack for many months or years at room temperature before someone buys it and eats it.  So you'd want to have everything pretty well killed off if you wanted to have that kind of safe shelf life.

    Most of my jerky is stored in the freezer vacuum sealed until I take a pack out, and then that goes away within a couple of days!

    Still, that document was pretty scary!

    I wonder how heating the meat while it's in its marinade, to 165° before smoking/drying it would affect the texture and flavor.  I always thought one of the things about jerky was that it COULD be done at fairly low temperatures in part because the salt curing made it hard for bacteria to survive.  I remember reading about old-time jerky being made simply by hanging the meat out on a rack in the sun and wind to dry.  Of course, back then they didn't know as much as we do now, but if it was killing people off, you'd still imagine people would have noticed.
  12. chef jimmyj

    chef jimmyj Smoking Guru Staff Member Moderator Group Lead OTBS Member

    Self Stability is not so much a function of killing any bugs that were originally there when raw, shelf stability comes from reducing the water content to the point that no bacteria, that was there or is introduced, can survive or grow.

    Heating in the marinade would definitely be the fastest method to get to a 165 IT and it would be as wet as you can get. In general meat taken to 165, in the oven, in the smoker, in a fryer, or in the marinade are going to be a similar texture internally. The surface will be drier with some cooking methods but overall the texture will be the same. Give it a try with lots of documentation as it will make a great post...JJ
  13. ussubmariner

    ussubmariner Newbie

    Are you referring to WATER CONTENT in the meat or ACTIVE WATER in the meat. It's different.
  14. sigmo

    sigmo Smoking Fanatic

    I may try it.

    And I might find a way to use a sous-vide immersion circulator in a large bath as the heat source so it won't go over 165.

    The main problem I anticipate with trying to heat it in a big pot on the stove is getting it all up to 165 without going well over that temperature and ending up boiling it like stew.

    Of course, for all I know, that might not necessarily produce a disagreeable result. Perhaps you would end up with a more tender jerky that way.

    Some experimentation wouldn't be a bad thing even if it's not a success. If I try it, I will document and post it.

    Tabbed in.
  15. chef jimmyj

    chef jimmyj Smoking Guru Staff Member Moderator Group Lead OTBS Member

    Considering that few members if any have the equipment to measure to see the water activity gets below 0.88, or the background or desire to understand the Water Activity being the ratio of vapour pressure of the meat to vapour pressure of pure water, there is little need to get into the science. However all, producer and first time smoker can understand..." shelf stability comes from reducing the water content to the point that no bacteria, that was there or is introduced, can survive or grow. " I keep answers simple and easily understandable unless asked to go into detail...

    Since you brought Water Activity up, for those interested, here is some more info...

     I see above is your First post so Welcome to SMF and please stop by Roll Call to introduce yourself and give us some background on your location, experience, equipment and smoking interests...JJ
    Last edited: Oct 20, 2016
  16. Me too. I've never cooked jerky in my life. Noone has gotten sick. Not saying that's the right thing to do....just sayin
  17. chef jimmyj

    chef jimmyj Smoking Guru Staff Member Moderator Group Lead OTBS Member

    Cooking to 160, adding cure #1 and especially all the above maintaining humidity just adds protection so " anybody " can eat it and not get sick...

    There are at ton of things we do everyday that Could put us in the hospital...Eating a Sandwich and flipping channels with the TV Remote, exposes your stomach to a whole variety of harmful bacteria. More so than eating off the Toilet Seat because most folks sanitize and clean the toilet at least once a week. Nobody cleans the Remote. Defrosting on the counter, Washing Dishes in barely hot water and puttin raw meat over salad ingredients in the refer...And No one ever gets sick...

    The average healthy adult Immune System has no problem eating Raw Meat, Air/Sun Dried Jerky with no cure, defrosting meat on the counter, the list goes on...BUT...Feed that same Raw Meat, Jerky or counter defrosted and undercooked meat to Grandma who has been sick, the neighbor that has HIV or my Asplenic Wife and they may be looking at a hospital trip. Commercial Jerky is prepared with humidity, and cooked, and uses Cure and Preservatives so no matter WHO eats it, they are not going to be a Litigant in a multi-million dollar food poisoning suit...JJ
    Last edited: Oct 20, 2016

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