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avalonsunrise

Forgot to adjust time for high altitude in canning

AvalonSunrise
10 years ago

Hello! I recently canned some peaches in syrup, apples in syrup, and pickled jalape�os. About a week later I realized that I had not adjusted my time for the altitude and should have added 10 more minutes of processing time to them. I called my local extension office and she said that they should be fine (not at risk for botulism), but that they would just spoil faster. Is this true? I would love to not have to throw it all out, but I would hate to make my family and friends ill.

Comments (20)

  • digdirt2
    10 years ago

    Botulism isn't usually a concern when dealing with acidic foods like most all fruits and with properly pickled items in a strong vinegar brine. The acidity provides the protection. Molds and yeasts are the concern and those you can see and smell.

    So assuming you followed approved instructions otherwise, yes they will be ok but will have a shortened storage life. Mark the jars and plan to use them within the next 3-4 months.

    The jalapenos will have the shortest storage since they are a low acid food and will gradually dilute the vinegar over time. You can extend their safe storage time a bit by refrigerating them.

    Dave

    PS: I wouldn't gift these to friends since you know they are less than ideal.

  • seysonn
    10 years ago

    About a week later I realized that I had not adjusted my time for the altitude
    *******************************************************
    What is the altitude of your location ? Under 1000ft, I wouldn't worry. Then if you use jiggler/hisser pressure relief weight, then altitude become irrelevant.

  • digdirt2
    10 years ago

    Then if you use jiggler/hisser pressure relief weight, then altitude become irrelevant.

    OP is talking about BWB processing not pressure canning and BWB processing times change depending on altitude.

    But the same is also true for pressure canning. For many foods the processing times as well as the weight used changes based on altitude.

    Dave

  • seysonn
    10 years ago

    Ok ! BWB is different because water boils at lower temperature at the higher altituded.
    ---------------------------------------------------------------------------------------
    But the same is also true for pressure canning. For many foods the processing times as well as the weight used changes based on altitude. (dave)
    ----------------------------------------------------------------------------------
    Yes, that is true if you are going by the gauge NOT the weight .
    Using different weight for different altitude is not necessary.
    The weight(any given weight) creates a universal pressure/temperature inside the vessel, anywhere on the planet of earth. We are talking about a given make and manufacturer.

    The reason for the above is that the weight is affected only by the gravitational pull of the earth not the atmospheric pressure. And the change in gravitational pull by altitude is negligible.

  • digdirt2
    10 years ago

    seysonn - I understand how weights work.

    Then if you use jiggler/hisser pressure relief weight, then altitude become irrelevant.

    Altitude never becomes irrelevant. One still has to know their altitude to know the proper weight to use for their altitude. And using different weights (5-10-15) AND different processing times for the same altitude, is recommended for several different foods.

    Altitude never becomes irrelevant. It determines the weight used and the processing time used.

    Dave

  • 2ajsmama
    10 years ago

    What I think seysonn is forgetting is that while altitude adjustment for gravity/weight is negligible and thereby often ignored, the boiling point of water is more dependent upon elevation, and the weight given for PCing at sea level (say 10 lb, or actually 10.5 psig) is based on a boiling point of 212, with the weight added to raise the pressure and achieve a temperature of 240. If the boiling point is below 212 at your altitude, the temperature reached inside the PC using that same weight will also be below 240. Hence higher weight (mimicking atmospheric pressure) and/or processing time at altitude.

    I found this chart online, wish I'd seen it when I asked my question about processing at 997ft. Boiling point of water at my house is almost 2 degrees lower than at sea level. It drops 1/2 degree (F) for every 250ft.

    Here is a link that might be useful: Boiling water vs elevation chart

  • AvalonSunrise
    Original Author
    10 years ago

    Thanks for all the input! Yes, I won't be giving these to any friends. And I'm sure we will have no issues eating these up fast. In fact, my husband will be incredibly happy to hear that he has to eat up the jalapenos soon. I'm glad to hear I don't have to throw them out though! It's nice to hear from more than one source. Oh, and my elevation is almost 5,000 ft above sea level. I knew about changing my weight to 15 when pressure canning, but had completely forgotten about the time for water bath canning. I can definitely say I will not forget to do that again! Thank you again!

  • seysonn
    10 years ago

    Altitude never becomes irrelevant. One still has to know their altitude to know the proper weight to use for their altitude. And using different weights (5-10-15) AND different processing times for the same altitude......(DAVE)
    ************************************************
    Selecting different weight , for different pressure/temperature and processing time, for different food items is well meaningful. But it has nothing to do with alltitude. In other words, weight system makes pressure valve type of control obsolete. Because any given weight will result in the same temperature/pressure inside the canner anywhere you go , from the see level to the top of Mount Everest.

  • calliope
    10 years ago

    I sat here and pondered what you were stating, seysonn because your argument sounds very logical. BUT........You are discounting the absolute pressure, and that's what makes your reasoning flawed. The pressure inside the cooker is not the only pressure exerted on the food you are processing. It is in addition to the atmospheric pressure outside of the cooker. At 5K feet, atmospheric pressure drops to around 12 psi instead of the nearly 15 psi of sea level and therefore the food is not as hot regardless of boiling point or amount of steam pressure inside the cooker. Is 3, 4, or 5 psi variation enough to make a difference? The safe established values are calculated with a higher absolute pressure..........so you can assume it does make a difference. Explained very well at this site (maybe you don't need it broken down so simply, but others might find this explanation easier to follow, so I'll use it for their benefit) so I'll link to it.

    Here is a link that might be useful: HIP pressure cooking

  • seysonn
    10 years ago

    @ calliope .... Your argument iwould be correct if you were just going by the gauge reading. Gauge reading is influenced by the atmospheric pressure (altitude). But when you are controlling the pressure with a weight on the vent, then the pressure inside the PC is independent of the atmospheric pressure. If at the same time you also have a gauge, it is not doing anything other than showing a pressure reading(psig), compensated by the atmospheric pressure. Because the PC is rigid vessel, the atmospheric pressure cannot influence the pressure inside it.
    In fact the weight is analogous to a spring loaded vent valve.
    Here is a quote from somewhere else:

    QUESTION:
    How spring loaded safety valve work in pressure vessel?
    In: Mechanical Engineering
    ANSWER:

    A spring loaded safety valve in a pressure vessel works by the pressure difference between pressure inside the vessel and spring force applied by the safety valve. if the pressure inside the vessel increases above the spring force its will open and allow the medium to flow out from pressure vessel.
    -------------------------------------------
    Note that atmospheric pressure has no effect here. The pressure inside be due hot or cold contents.

  • calliope
    10 years ago

    I'm sorry......it's not my argument. It's the argument of food scientists who set up the guidelines for assurance of food safety. I didn't sit here and come up with that theory based on my understanding of physics. It's spelt out in the link I provided and addresses BOTH gauge and weight cookers and the principle is the same. Atmospheric pressure cannot be discounted as an important variable independent of the confined steam pressure inside a vessel. You are certainly welcome to your opinion, and I don't expect to change it. But, I'd also recommend that canners coming to this forum accept the standard recommendations put forth by universities who say that atmospheric pressure does impact processing time with both weight and gauge cookers.

  • 2ajsmama
    10 years ago

    The weight on the vent is just ADDING to the atmospheric pressure. As calliope said, the assumption is that you are operating at or below 1000ft so atmospheric pressure is app 15 psi or greater. Recipes are written with this assumption so if a recipe says to process at 10 lbs weight (or 11psig by gauge) for a certain amount of time it is assumed that the pressure will be that 14-15psi plus the 10-11 as explained in the link calliope gave (actually you have to click on another link so I've put direct link below for pressure cooking at altitude).

    Weight is weight, you're correct we don't recalibrate our scales depending on altitude but you are missing the whole point that whether you are going by the gauge (which is calibrated, if not off, for sea level atmospheric pressure, so shows 0 psig - the g for "gauge") or the weight that is just in addition to the atmospheric pressure at your location which can vary widely.

    But as calliope said, if atmospheric pressure is lower then you need to compensate by adding weight and/or time - in the example given in the link below, at 5000ft the pressure is 12.2psi (absolute, not psig - "gauge referenced at sea level"), 2.5 psi LOWER than at sea level so theoretically you need to add 2.5 lbs of weight to the vent. Since the weights only go in 5 lb increments (and pressure cookers don't tend to use weights), you would in the cooking example add time as shown in the chart on the link.

    For pressure canning at 5000ft the NCHFP has you add 5lbs to whatever the "below 1000ft" weight is for the recipe, if you are using weights, and if you don't have a weight set then you just have to adjust the heat to maintain 2psig higher reading on your gauge than you would use at sea level (since chart - I'm using the one for tomatoes - goes from 4001-6000ft, they haven't done charts for every 250 or 1000ft).

    To the OP: I know you were talking about BWBing, and I'm glad you got your answer. Sorry for the hijack but it's important to address this issue since it was raised on this thread and you never know who's going to be reading it in the future.

    Here is a link that might be useful: Direct link to pressure cooking times at altitude

    This post was edited by ajsmama on Mon, Sep 30, 13 at 9:36

  • 2ajsmama
    10 years ago

    Another useful link - chart of pressure (absolute, or psia) at various altitudes:

    Here is a link that might be useful: Atmospheric pressure vs altitude

  • seysonn
    10 years ago

    OK everybody. You do whatever you think is right.
    As i said before WEIGHT acts just like a spring valve and it will open/pop/hiss/ giggle when the pressure inside the vessel has reached to a predetermined point. The vessel (Pressure cooker, pressure canner) is a closed mechanical system independent of atmospheric pressure , just like boiler(steam or water), hot water heater. Same principles. BUT THE PRESSURE IN THE TIRE IS NOT. A PRE INFLATED TIRE AT SEA LEVEL (taken to another location) WILL HAVE DIFFERENT PRESSURE , DEPENDING ON THE ALTITUDE.

    There are two methods to set/control the pressure inside a pressure cooker:

    1) old fashioned weight system.
    2) Dial system ( by tightening or loosening a spring relief valve)

    When a pressure cooker is designed to create , eg, 15 psi standard pressure inside it, that make and model with that weight or pressure setting will always create 15 psi, no mater where on the face of Earth it is operating. IT IS A CLOSED MECHANICAL SYSTEM.

    p.s.
    PRINCIPAL DIFFERENCES BETWEEN A PCanner and PCooker:

    1) canners are generally taller and have larger capacity.
    2) caners have(can) have more than just one pressure setting, to accommodate to process different foods at different pressure for different length of time.

    THE ALTITUDE QUESTION only relates to BWB canning.

  • 2ajsmama
    10 years ago

    seysonn - you are correct that the ONLY differences between a pressure cooker and a pressure canner are 1) capacity (has to be able to hold 4 quart jars to be used as a canner) and 2) settings (pressure cookers usually only include a 15 lb regulator, and recipes are written to be processed using that regulator, though if you follow the link calliope gave you will see that the operating pressure is usually lower, and varies by manufacturer).

    So the principle is the same, I don't know how else to explain it so I'm going to stop trying. Do whatever you think is right for your own preservation (BTW, what is your background? I have a Master's degree in Electrical Engineering, which required 2 years of physics). But please don't try to convince other people to use improper processing methods.

    According to the NCHFP, altitude DOES matter when pressure canning, if someone is concerned with safety and wants to process food properly at altitude, they should use NCHFP approved recipes including proper weight and time for processing.

  • calliope
    10 years ago

    I have a background in engineering as well, ajsmama in an engineering evaluation laboratory for a major manufacturer as well as two other venues, but figured if I threw that in, I'd just be accused of making it up to prove my point so I saved my breath.

  • seysonn
    10 years ago

    Posted by ajsmama 5b (NW CT) (My Page) on
    Mon, Sep 30, 13 at 9:52

    Another useful link - chart of pressure (absolute, or psia) at various altitudes:
    ***************************************
    The link that you provided, explains the variation in atmospheric pressure by altitude. I know all that stuff.It is more relevant in open systems.

    The argument made in the link that calliope provided is valid in general, but when it comes to pressure cooker, is not, when a spring loaded gauge or a weight is used. But if the gauge is diaphragm type then it is a valid argument. If a pressure cooker or pressure canner utilizes solely such a gauge then I must say that it has become obsolete that is why PRESTO has come up with variable (5, 10, 15 lbs) weight system. With the weight system there is no need to make adjustment fo altitude.
    PRINCIPAL;
    When you are pressure cooking or canning, the goal is to generate a certain level of temperature to kill the bacteria. That is why there are dfferent pressure(really temperature) requirements for different foods, based on their acidity. This means that by inflating a canner with an air pump- you are not going to get that result. The 14.7 psi of atmospheric pressure (at sea level)make no more contribution towards that end than a 9.7 psi pressure at 15000 ft elevation(just example). So how much pressure you add by heating beyond those pressures is what counts. That is why the simple weight system make a universal approach to pressure cooking/canning.

    P.S.
    (BTW, what is your background? I have a Master's degree in Electrical Engineering, (ajsmama)

    Now that you asked: I am a degreed Mechanical Engineer, specialized in Heat and Mass Transfer and HVAC. .

  • kvenkat
    10 years ago

    I am at 6000 ft and have made it a habit to write on any new recipe the additional time required for waterbath processing, usually an extra 10 minutes.

  • myfamilysfarm
    10 years ago

    Kvenkat, that makes sense, just change the times and weight right on the recipes. I'm lucky enough not to worry about it.

  • morz8 - Washington Coast
    10 years ago

    I find notes really helpful, I keep note cards in my canner when its stored. Yield (ie how many pounds of tuna gave me x number of jars), how many jars of something we used a previous year, all kinds of things I think I will remember - but never do.

    My cookbooks all have notes in the margins, recipes I tried that we liked, things that didn't go over so well (so I won't make them again), substitutions I've made that were successful....I'd do the same with my canning books if I were not at sea level, I trust very little to memory any more - life is just too busy :)