limiting the nasties in stored iced tea
i wrote last year about making tea in a coffee machine, but it wasn’t until recently that i stopped to think of something i’d noticed: the tea i brew in my coffee machine keeps for days at room temperature.
if you’re not an iced tea fanatic, that might not mean anything to you. however, anybody ordering iced tea regularly in restaurants finds that tea kept at room temperature can get funky damned quickly. i’ve almost given up on ordering it out, because of that foul odor and taste. in one of those wonderful discovery moments that apparently never stop arriving, i finally took the time today to think about it.
i theorized, and internet research backs me up, that the primary reason my tea keeps so well is that it’s being brewed at high temperature, killing the bacteria in the tea leaves. i’ve only used two different types of tea so far in my coffee machine (lipton standard and twinings earl grey), and both appear immune from the rancid tea syndrome of many restaurants. may not seem like such a big deal, but it’s a problem most restaurants haven’t yet solved.
when we made tea at my old restaurant in the 80s, it was with hot tap water. we’d fling a big tea bag or two into a plastic jug, fill it with hot water, and let it sit. still, our tea rarely was bad, because the restaurant would close between lunch and dinner, and we’d throw everything out. reading tonight about other restaurant practices, i’m not surprised by the result:
Restaurant iced tea is a notorious source of coliform bacteria. Our lab students have done studies which have shown that the tap water supplies at local restaurants are OK; homemade, freshly-brewed tea is OK; and freshly-brewed, restaurant iced tea is OK, but restaurant iced tea that has been sitting at room temperature for any length of time (as well as a sample of home-brewed tea that was added to a “dirty” pitcher) can have as many as millions of coliform bacteria per 100 mL of tea. In talking with students who work at some of these establishments, a repeating picture begins to emerge. In most cases, the tea is stored at room temperature in large, plastic-lined urns. Whenever the supply in an urn is getting low, the typical procedure is to make more tea and add this new, lukewarm tea to what is already there. In places that are open on a 24-hr basis, this goes on continually. In places that close for a few hours each night, any remaining tea is drained into a plastic pitcher, placed in the refrigerator overnight, then poured back into the urn (which, at most received a cursory rinse the night before) in the morning. Seldomly are the storage urns thoroughly cleaned and sterilized, and students have reported that when they have had to clean one of these urns, the insides are typically coated with slime (= bacterial growth). Typically the restaurants with the cleanest tea have taken the following steps:
- tea is stored in a stainless steel-lined container
- tea is quickly chilled after brewing and held at a cool temperature
- tea is made in smaller, more frequent batches
- the container used to store the tea is THOROUGHLY scrubbed clean and sterilized before EACH new batch of tea is added
- new tea is NEVER added to or mixed with “old” tea
- the urn is thoroughly sterilized at the end of each work day and left clean and dry overnight
- tea is not saved overnight for use the next day
- tea is not allowed to sit in the urns for more than a few hours before it is considered to be “expired”
Many other restaurants have “solved” this problem by switching to instant or other pre-packaged tea, thereby sacrificing flavor for convenience rather than taking the time to keep equipment clean. Consider that at home, most people typically make a pitcher of tea at a time, keep it refrigerated until use, then thoroughly wash the pitcher before adding a new batch of tea to it. If you want iced tea at a restaurant, order a cup of hot tea and a cup of ice, and make it yourself.
from what i’ve seen, the biggest factor is heat in brewing — something that site, surprisingly, doesn’t mention (though this one does). i don’t even wash my tea (coffee) pot. i just rinse it a bit, then do my thing. i never refrigerate the tea. i let it reach room temperature naturally, sitting on the warmer which i turned off only after the batch was made. i do not ever mix batches, however, and i think anybody doing that at home or professionally for any food or drink (well, except maybe for sourdough bread or something like that) is a nut. oh, one other thing i do is not put the empty pot under the thing right away, letting the basket fill just a bit (this model has that valve over the pot, which i guess is standard now), and give the hot water a little more time with the tea leaves.
something else that might make a difference is that i add a little sugar most of the time. not being a biologist, i can make bullshit arguments for why sugar would both slow or speed a bacteria/fungi problem. given how little i use, i think it hurts, if anything. don’t know that, and won’t be testing it, but i do know that the way most restaurants, delis, etc. prepare/store tea is a joke. most of the time i’ve asked for a refund or a change of drink because of rancid tea, the people on the other side of the counter couldn’t care less about the problem. but why should that be any different from anything else?
i wonder how many people have stopped drinking iced tea in restaurants because it’s nasty. in the 70s, my family ate at the same roy rogers fast food restaurant for years, and i drank mostly iced tea (with Sweet’N Low, which i loved the taste of as a kid). every once in a while the tea had that moldy, rank taste, but i just got used to it, figuring it was something i didn’t understand. 
oh, the trust of youth; incompetence would have been the last thing i suspected, and now it’s the first.