Introduction: How to Make a Kitchen Sized Immersion Chiller to Radiply Chill Tea (for Iced Tea), Stocks, Broths, and Brines
Confession: I'm a Tea snob (so yeah, I'm not a tea bag guy - loose leaf all the way). Tea is the World's most popular beverage...yet many people are either unaware or intimidated by all the options out there. A quick primer: ALL tea comes from the same plant, Camellia Sinensis, basically picked leaves/buds from new growth. The difference is in how it's processed after it's picked. There are 6 main types (white, green, black, oolong, yellow, and fermented teas like pu-erh). If your picked leaves are quickly dried, you have white tea. If your leaves are withered first to remove some moisture and then dried, you have green tea. If your leaves are crushed and rolled and left to oxidize (imagine if you crumple some Basil or other herb and leave it out...it turns brown - same thing with tea) and then dried - you have black tea. Etc. The stuff you get in tea bags is still tea, but mostly low quality and it may well have been sitting on the store shelf for up to 2 years. Don't buy it unless you know it's good stuff - there is high quality teabag tea out there, but you have to seek it out.
There is fresh, high quality tea easily available online - go get you some and I guarantee you won't go back..
So - when I'm making tea for iced tea, I like to make a large batch (usually a gallon or two at a time), using a fresh and exquisite loose leaf green tea. I make a lot more iced green tea than black tea, but it's really just my preference. Sometimes I'll make an iced black, when the mood strikes...like when a superb first flush Darjeeling comes in :)
The problem is that a large batch (say 1 gallon) of freshly made tea will take ages to cool down sufficiently before you can put it in the fridge. I have the same issue when making stocks and broths, where the problem is exacerbated because leaving those liquids out at room temperature for extended periods while it slowly cools can encourage the growth of bacteria and other nasties. You can ruin your entire batch, or worse you can sicken or kill your entire family - so basically you want to chill your liquid as quickly as possible and refrigerate to keep pathogens at bay.
There are ways to cool large quantities of liquid, but they involve coolers full of ice and are generally a laborious process. What you don't want to do is put a gallon of hot liquid straight in the fridge or freezer, as it will just warm everything else up and still take ages to cool. If it's Winter and freezing out, then no worries - you can just stick it outside to cool...but iced tea is far more popular in Summer so this may not be an option..
Now to the point of this instructable: you have a large quantity of hot tea, which will take ages to cool down before you can put it in the fridge. What to do?
I decided to make a small, kitchen sized immersion chiller to rapidly cool my teas so I can get them straight into the fridge. Similar to what home brewers use to rapidly chill their wort. It will also be an excellent tool when I make large batches of meat or chicken stock. Or when I need to brine a pork shoulder overnight but only remembered to make the brine at 9pm and need to cool it rapidly :)
How does an immersion chiller work? Basically you run cold water from the faucet via a hose and through a copper coil and then out of the coil at the other end, while the coil is immersed in your hot liquid - in this case, green tea. Copper is a great conductor of heat, and the heat from the tea is transferred by the copper to the cold water running through it. You will notice that the water exiting the coil will be warmer, having robbed the heat from the liquid you're trying to cool.
The result is that you can cool down a hot liquid quite rapidly, and then get it straight into the fridge. Instead of waiting for hours for it to cool down on it's own, and risk funky stuff growing in it.
I have been thrilled with how well it works - it cools a 1/2 gallon of hot tea/stock in under 4 minutes! Then straight into the fridge.
I timed how long it took to make a gallon of green tea - using my 4cup French Press for four steepings (each about two minutes) with water at 170-180 degrees F. The entire process from dry leaf to 1 gallon of cool green tea: just under 15 minutes! You will see my process at the end of this instructable. Seriously one of my better hacks - so I hope this helps others who have a tea fetish or other need to cool quantities of hot liquid quickly.
Step 1: Making the Immersion Chiller - Things You Will Need
What you will need:
- Some soft, bendable Copper pipe from your local big box (I had some 3/8" copper laying around from a previous project, so used that. You can buy various sized piping - I would suggest not too large diameter so it will be easier to bend. What you DON'T want is the straight copper pipe as it's a different composition and a lot harder than bendy copper pipe. The right pipe will be coiled when you buy it. Probably need 3-4' length, although I confess I didn't measure mine - it was a leftover.
- Strong heat source - either a propane torch, a high BTU jet burner outside, possibly even a gas ring on your stove. This will be to anneal (soften) the copper ready for bending into the coil.
- Thick gloves and a wrench or other means of holding the pipe while you heat it.
- A pipe bending spring (although there are other ways to do it, discussed later on)
- A round form - I used a full can of glazing putty that was about the size diameter I needed.
3/8" inside diameter poly hose (to match the 3/8" outside diameter copper pipe for a snug fit). How long will depend on how far from the sink you will be, and remember you will need twice the length for hose - supply and return. Type of hose isn't important, as the cooling water won't come into contact with your tea/stock.
- Hose clamps, if necessary - to clamp the hose onto the copper pipe. I didn't end up using them as the hose was a nice tight fit and didn't leak .
A nylon hose barb with 1/2" male thread. This would screw into my faucet (but please note that most faucets have a much finer thread so get one to match your faucet. If it hadn't worked out for me, my next attempt would have been one of those cheap hand-shower attachments for a kitchen sink, the one with a rubber cone that you push onto the end of the faucet. I have a feeling that would have worked as well.
Step 2: Anneal the Pipe to Make It Bendy
The first step is to anneal the pipe. This is basically to soften the metal and make it easier to bend.
You do this by heating the pipe until it has a pinkish glow and then let it cool. Copper is also convenient in that you can cool it rapidly by plunging in water or let it cool slowly/naturally - not all metals have this property, but handily, copper does.
You can use a propane torch if you have one, I used my outdoor jet burner (the type you get for Turkey fryers) as it was a lot faster.
Use gloves, and hold the pipe with a wrench or similar, as the whole pipe will get red hot. Remember that's why you're using it - because it's an excellent heat conductor. Move it around and make sure you heat it evenly over the entire length you'll be bending. It changes color so you can track your progress as you go.
Cool it fast or slow, and you're ready to bend it into the coil shape.
Step 3: Forming the Coils
Once the pipe is fully soft/annealed, it's time to form the coil. I used a pipe-bending spring I've had for years - you can get them at the hardware store (mine came in a set for various diameter piping - use the spring that's sized for the pipe you're using).
There are many ways to bend pipe without kinking it...you can fill it with sand and hammer the ends closed, form the coil and then cut the ends off and pour out the sand. Some advocate filling with water and freezing for the same effect. Basically you want to bend the pipe without kinking it, which means supporting the pipe internally or externally while bending.
Working slowly, bend the pipe around your form, in my case a conveniently sized can of window glazing. I slid the bending spring along the pipe as I went.
You want both ends upright and close to each other so it will be easier to wield once you're using the chiller - I spot annealed again at the upright bends with a propane torch just to ensure I didn't kink the pipe after all that hard work.
Voila - the bending into a coil also has the advantage of hardening the copper again, so the finished coil is pretty solid and won't need further support. A final jiggling to get the coils equally spaced and looking all purdy. It's now ready to get cleaned up and attached to hoses ready for use.
Step 4: Add the Hoses and Faucet Connection
Finally I gave the immersion coil a good cleaning and then attached the vinyl hoses to the intake/exhaust, and pushed on the faucet adapter to the intake end of the hose. The immersion cooler will be in contact with some high quality green tea, homemade beef and chicken stock, etc., and cleanliness is next to godliness...so take the time to clean it well.
There are a few different methods to clean copper...anything acidic will work, I used a vinegar/salt solution to give it a thorough clean and remove all the oxides, then a good soapy water wash.
There might be exact proportions you're supposed to use, but my guess is I used 1/8 vinegar to water ratio, plus maybe 3 tbs salt in a 2 QT container and let it soak for an hour or so. Most internet experts seem to recommend a periodic vinegar soak to get it pink and clean, but the main thing is to clean it after each use with a good soapy wash and rinse.
Step 5: Take Your Coil for a Test Drive - Make a Large Batch of Green Tea
Okay - time to make a batch of iced tea, your own iced green tea, a large flagon of it ready to consume in the fridge at all times. And not just any green tea, but the absolute best quality tea there is out there. Using my setup, I made 1 gallon of green tea, and it was in the fridge in under 15 minutes.
As far as tea goes, green teas (sipping cup for cup) can often contain less caffeine than black teas, which contain about half the amount of caffeine as coffee - so drinking tea is a great way to enjoy the World's most consumed beverage and not be too concerned about caffeine intake (especially in the evening). If you're sensitive to caffeine, obviously you'll need to find a product that works for you. For iced tea, I usually go green or white tea, and I'm always trying new varieties from tea gardens around the World.
If you're new to tea, please don't buy your tea at the grocery store - chances are good that it will have been on the shelf for up to two years. Tea will easily pick up any surrounding odors, so depending on how well it was packaged it could taste, subtly, of anything. That, or it will taste like liquid cardboard because it was low quality to start with. And don't assume that the tea emporium at your local mall is any better because they specialize. Their tea will sit on the shelf until it's sold as well. There are many sources online for fresh, high quality tea, that could have been on the bush just a few weeks ago. Plus you can also find Fair Trade or Organic varieties if you want. Go explore.
So treat yourself and get the good stuff - it doesn't cost much more and the taste difference will have you hooked for life. And please please please avoid mass produced teabags!! Rant over.
Okay. Having just finished a wonderful bag or "Nine Glorious Mountains", and with my last batch a beautiful "Clouds and Mist Green", I decided to go with the "Pi Lo Chun Imperial", always a winner! (I'm on a Chinese green tea binge at the moment.)
And here is a Green Tea secret: the highest quality Green Teas allow for multiple steepings/infusions from the same pot. You can't do it with many black teas (in general at least - the oxidation process combined with smaller resultant leaf size and boiling temp will produce bitter/astringent flavors and tannins if you try to re-steep), but greens are steeped at a much lower temperature (anywhere from 160-180 degrees F) and only for a couple of minutes at a time, and therefore don't release the bitter tannins that affect the taste until much later.
For a quality green tea, you can reliably get 4 steepings from the leaves, for the highest quality teas it can keep on going. You get great bang for your buck, plus a wonderful flavor balance (the different complex compounds extract at different rates depending on water temperature and how the leaves unfurl). I know - probably more than you wanted to know!
1. Get your water heating...target the 170-180 degree range, depending on your tea. (Fancy kettle like mine, instant-read thermometer, or practice and become an expert in reading when the 'tiny bubbles' equate to the target temp). Do not boil the water, or it's game over and ruined tea.
2. Measure out the tea leaves into the French Press. (Mine is a 4 cup press - use 4 generous teaspoons (1 per cup), or if weighing it would be 5 grams per cup or 20 grams).
3. Steep the first lot for 2 minutes, while topping up the kettle and heating the water again.
4. Once steeped, plunge and pour out brewed tea into a cooling container - I use a 2QT glass jug. By this time your water is back up to temp in the re-filled kettle.
5. Repeat...in my case, 4 times. Sometimes I do an extra one so I can be sipping some hot green while we wait. You will notice with each successive infusion how the dried tea leaves unfurl and expand as they hydrate - it's pretty cool to watch.
6. Now would be the time sweeten, if that's your thing. I don't ever sweeten mine, but if you do, I suggest adding honey or other sweet while it's hot, before chilling.
7. Here we go! Hook up the immersion chiller to the kitchen faucet, turn on the water. I swirled the tea with a spoon inside the chiller coils so that the hot tea is constantly moving over the cooling coils. The tea was cooled in under 4 minutes. I did this twice in my 1/2 gallon glass jug to fill two 2-quart containers.
8. Pour yourself a cup of tea, over ice. Taste test.
9. Pour the cooled tea into a container with lid and get 'er in the fridge.
10. Time for a nice cup of tea and a sit down.
11. In our family, we can consume iced green tea in great quantity, especially in the Summer. This has made the process quick and easy, which is all we ever really want, right?
A final tip - think all green tea is the same? Here's a challenge - do a blind taste test with a few different ones and you will be shocked at how different each one is. For starters I would suggest a Japanese Sencha, a couple of Chinese varietals (perhaps gunpowder and a high mountain green), and maybe an organic green from India or Africa? Side by side, you will immediately notice the 'grassy' notes of the Sencha, the floral Chinese etc. Maybe throw a Jasmine into the mix. Jasmine, btw, is just green tea flavored with jasmine flowers.