7 votes

Everything you need to know about dry-aging duck at home

7 comments

  1. [7]
    whisper
    Link
    I'd love to attempt a project like this in the comfort of my apartment kitchen. However, my meager understanding of kitchen safety limits me to in-fridge quick pickling. I want to ferment and age...

    I'd love to attempt a project like this in the comfort of my apartment kitchen. However, my minor germaphobia fear of dying alone from foodborne illnesses meager understanding of kitchen safety limits me to in-fridge quick pickling. I want to ferment and age things. I even have a 6-month batch of aged eggnog in my fridge that I'm afraid to sample (what if there's salmonella in it?).

    How do these ducks not all go rotten? How do people regularly age game out in cool areas and not just die all the time from spoilage?

    How can I be sure my eggnog is not teeming with hostile bacteria before drinking it?

    3 votes
    1. [3]
      patience_limited
      (edited )
      Link Parent
      Your aged eggnog, assuming you used an aging-specific recipe, has about 20% ethanol and a considerable amount of sugar. It shouldn't support pathogenic bacterial growth if stored under...
      • Exemplary

      Your aged eggnog, assuming you used an aging-specific recipe, has about 20% ethanol and a considerable amount of sugar. It shouldn't support pathogenic bacterial growth if stored under refrigeration for at least a few weeks. If Forbes is to be trusted, this is actually a traditional method for preserving eggs into the winter months, from the days before hens could be coaxed to lay during winter using artificial light.

      Aging meat operates through similar principles. Basically, growth of food poisoning bacteria is inhibited under any of the following conditions:

      • Temperature below 3.3°C/38°F. Some non-pathogenic bacterial and mold growth continues, and can result in spoilage odors and slime after about 14 days at this temperature.

      • Reduced water activity. The explanation is a little complicated, but you can reduce it with high concentrations of sugar or salt, or by drying the food. You're essentially ensuring that the bacteria don't have any means of transporting food through their membranes, or actually bursting them with osmotic pressure differential.

      • Strong acids and bases - these denature bacterial membrane proteins or otherwise inhibit growth

      • Ethanol - disrupts bacterial lipid membranes at high enough concentration. It's part of how yeasts have evolved to outcompete bacteria in some environments.

      • Heat - maintaining a temperature above 140°F for a few minutes disrupts most bacterial proteins. ***Botulinum and some Bacillus spores take special cooking measures for anything to be stored at room temperature.

      So when you dry-age duck, you're both inhibiting bacteria through refrigeration, and lowering the water activity of exposed surfaces by allowing them to dry.

      5 votes
      1. [2]
        whisper
        (edited )
        Link Parent
        I followed Alton Brown's Aged Eggnog recipe. I did the math when I originally made the batch. I don't recall the exact numbers, but I believe the ethanol content was in the 12-16% range (plus the...

        I followed Alton Brown's Aged Eggnog recipe. I did the math when I originally made the batch. I don't recall the exact numbers, but I believe the ethanol content was in the 12-16% range (plus the pound of sugar).

        I was fine with that level, until I saw all the results quoting the 20% ethanol level as being tested to effectively kill bacteria and prevent growth. It's not logically sound, but my thought process is "Well, the minimum level that's been tested to kill bacteria is 20%, therefore anything less is unsafe."

        I know that's not cogent.

        2 votes
        1. patience_limited
          (edited )
          Link Parent
          The pound of sugar will do it if the ethanol alone won't. But really, ethanol above ~11 - 12% will tend to inhibit bacterial growth; that's about where natural yeasts stop growing, and they've...

          The pound of sugar will do it if the ethanol alone won't. But really, ethanol above ~11 - 12% will tend to inhibit bacterial growth; that's about where natural yeasts stop growing, and they've outcompeted the bacteria at that point.

          All that being said, I'd invest in a $10 refrigerator thermometer; they're more accurate than whatever the 'fridge manufacturer supplies, and required for commercial kitchens to pass safety inspection. Place it near whatever critical product you're trying to preserve, like an air-drying duck.

          3 votes
    2. [3]
      MatterHorned
      Link Parent
      Salmonella isn't really a big deal unless you already have a compromised immune system. It only kills a few hundred people every year in developed countries like America, despite infecting...

      Salmonella isn't really a big deal unless you already have a compromised immune system. It only kills a few hundred people every year in developed countries like America, despite infecting millions. Botulism is the real killer.

      Anyway, the reason cooking food protects you from illness is because it creates an inhospitable environment for harmful bacteria, inhibiting their growth. The same thing happens when you cure, age, or refrigerate foods. They're all just different ways of inhibiting bacterial growth.

      4 votes
      1. [2]
        whisper
        Link Parent
        Thanks, now I'm worried there's botulism growing in my aged eggnog's mason jars.

        Thanks, now I'm worried there's botulism growing in my aged eggnog's mason jars.

        1. spit-evil-olive-tips
          Link Parent
          As long as it's been in your fridge the entire time, you're almost certainly safe. Botulism won't grow in temperatures below 50 F. If you left your eggnog out at room temperature for several days,...

          As long as it's been in your fridge the entire time, you're almost certainly safe. Botulism won't grow in temperatures below 50 F. If you left your eggnog out at room temperature for several days, in theory botulism could grow...but there'd be several other reasons you wouldn't want to drink that eggnog.

          Also, Alton Brown knows what he's doing, so as long as you followed his recipe, that's an extra layer of safety.

          The main risk of botulism comes from unrefrigerated homemade things. Homemade garlic oil is a common one, for example:

          To reduce this risk of botulism, the garlic in oil mixture should be refrigerated and used within two to three days. Garlic-in-oil should always be discarded after two hours at room temperature, even if salt and acids are present. Commercially prepared oils have added acids and other chemicals to eliminate the risk of botulism, but still must be handled carefully and correctly.

          Low-acid foods canned at home are another common vector.

          3 votes