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Fungus and mold will likely appear if you brew anything with water at room temperature. Use the fridge - trust my experience. It may take a bit longer to brew

Fungus and mold will likely appear if you brew anything with water at room temperature. Use the fridge - trust my experience. It may take a bit longer to brew at colder temperatures, due to decreased convection of the liquid, but it will taste much better, as it prevents bacterial and fungal growth.

hericium 4y ago
I believe fungi aren't too fond of caffeine.
- goldenkey 4y ago
  Perhaps, but I've cold brewed black tea enough times with moldy results to forewarn y'all.
- yunohn 4y ago
  Mold (a fungus) has grown in my refrigerated cold brew enough times for this to be false. More here - https://kitchenappliancehq.com/can-cold-brew-coffee-mold/ https://kitchenappliancehq.com/can-cold-brew-coffee-mold/
  - traverseda 4y ago
    Huh... that hasn't been my experience. I notice that article uses a lot of affiliate links, are you sure it's not fear-mongering in order to sell it's special cold brew coffee maker? Not saying that mold is impossible, but I don't think the solutions is to buy their amazon affiliate coffee maker and special coffee butter. If you have mold issues after 24 hours of cold brewing I think you have some deeper issues at play. Consider getting mold tests for your house, sterilizing the tools/containers you use, and switching out your beans.
    - yunohn 4y ago
      I wasn’t endorsing the article, merely providing it as evidence of mold following my anecdote. I generally face it 3-4 days in, not 24 hours.
- DontchaKnowit 4y ago
  As someone who has terrible kitchen cleaning habits- definitely not true lol. Wet coffee grounds will grow mold quicker than any other food product I've seen. Even a pot of coffee will get mold on the top within like a week.
  - foobiekr 4y ago
    I wonder if this is that the grounds, post use, are somewhat sterilized and vulnerable to rapid colonization.
    - goldenkey 4y ago
      I believe it has more about the lack of airflow and the compaction and moisture.
traverseda 4y ago
I'm not a doctor or a biologist. But I do have a water cooler and have brewed both alcohol and cold brew in the past. There's no super special sterilization process for cold brew, we don't use sterilite on the spike that opens up the bottles, we don't store the water in an especially cool place, or otherwise take any special precautions. That water turns out fine, often for weeks at a time. Store the cold brew out of direct sunlight, don't leave the grounds in for a super long time, and you'll be fine. It's not like brewing alcohol, you're not adding a bunch of sugar to it or anything like that. The coffee grounds you're adding are shelf-stable, the water you're adding it to is shelf-stable, you're not introducing any real food for bacteria/fungus. Water will eventually go off if you leave it in direct sunlight (mostly due to algae), especially after introducing extra organic matter, but the actual risks of following established methods for brewing cold-brew at room temperature are very low in my opinion. Especially chlorinated water like you probably get out of your pipes.
krageon 4y ago
This is nonsense. Fungus and mold takes a while to develop, and most probably that timeframe is not over night in ground coffee (or tea). It is still better to do it in the fridge, because if you put it straight in it's less work and tastes good if you leave it overnight.
- goldenkey 4y ago
  Overnight, sure. But I like my extracts/brews super strong. After a couple of days you will get mold growth.
  - IIsi50MHz 4y ago
    Cold-brewing can reliably be done at food-safe refrigerator temperatures over multiple days, safely. The longest brew I've heard used at any coffee shop is 8 days, though I've never tried more than 5 (usually 1 to 3).
    - goldenkey 4y ago
      Right, that's what I'm saying. If you try to cold-brew non-refrigerated for more than a day, you'll get mold.

hericium 4y ago

I believe fungi aren't too fond of caffeine.

goldenkey 4y ago
Perhaps, but I've cold brewed black tea enough times with moldy results to forewarn y'all.
yunohn 4y ago
Mold (a fungus) has grown in my refrigerated cold brew enough times for this to be false. More here - https://kitchenappliancehq.com/can-cold-brew-coffee-mold/ https://kitchenappliancehq.com/can-cold-brew-coffee-mold/
- traverseda 4y ago
  Huh... that hasn't been my experience. I notice that article uses a lot of affiliate links, are you sure it's not fear-mongering in order to sell it's special cold brew coffee maker? Not saying that mold is impossible, but I don't think the solutions is to buy their amazon affiliate coffee maker and special coffee butter. If you have mold issues after 24 hours of cold brewing I think you have some deeper issues at play. Consider getting mold tests for your house, sterilizing the tools/containers you use, and switching out your beans.
  - yunohn 4y ago
    I wasn’t endorsing the article, merely providing it as evidence of mold following my anecdote. I generally face it 3-4 days in, not 24 hours.
DontchaKnowit 4y ago
As someone who has terrible kitchen cleaning habits- definitely not true lol. Wet coffee grounds will grow mold quicker than any other food product I've seen. Even a pot of coffee will get mold on the top within like a week.
- foobiekr 4y ago
  I wonder if this is that the grounds, post use, are somewhat sterilized and vulnerable to rapid colonization.
  - goldenkey 4y ago
    I believe it has more about the lack of airflow and the compaction and moisture.

traverseda 4y ago

I'm not a doctor or a biologist. But I do have a water cooler and have brewed both alcohol and cold brew in the past. There's no super special sterilization process for cold brew, we don't use sterilite on the spike that opens up the bottles, we don't store the water in an especially cool place, or otherwise take any special precautions. That water turns out fine, often for weeks at a time. Store the cold brew out of direct sunlight, don't leave the grounds in for a super long time, and you'll be fine. It's not like brewing alcohol, you're not adding a bunch of sugar to it or anything like that. The coffee grounds you're adding are shelf-stable, the water you're adding it to is shelf-stable, you're not introducing any real food for bacteria/fungus. Water will eventually go off if you leave it in direct sunlight (mostly due to algae), especially after introducing extra organic matter, but the actual risks of following established methods for brewing cold-brew at room temperature are very low in my opinion. Especially chlorinated water like you probably get out of your pipes.

krageon 4y ago

This is nonsense. Fungus and mold takes a while to develop, and most probably that timeframe is not over night in ground coffee (or tea). It is still better to do it in the fridge, because if you put it straight in it's less work and tastes good if you leave it overnight.

goldenkey 4y ago
Overnight, sure. But I like my extracts/brews super strong. After a couple of days you will get mold growth.
- IIsi50MHz 4y ago
  Cold-brewing can reliably be done at food-safe refrigerator temperatures over multiple days, safely. The longest brew I've heard used at any coffee shop is 8 days, though I've never tried more than 5 (usually 1 to 3).
  - goldenkey 4y ago
    Right, that's what I'm saying. If you try to cold-brew non-refrigerated for more than a day, you'll get mold.