A fizzy, tart electrolyte drink for training. Made from black tea, cabbage brine and whatever fruit peels you have, it runs in one 5-liter jar and gives you a liter a day.
4 Lbrewing in the 5 L jar
1 L/dayharvest and feed back
~600 mgsodium per liter
Pinkon the red-cabbage test before drinking
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Why brew your own
A sports drink with live cultures
Store sports drinks replace the salt you lose in sweat, mostly with sugar and flavoring. This tonic replaces the same salt, adds live lactic-acid bacteria and costs about as much as a cup of tea.
More sodium, less sugar
Sweat is mostly salt and water. The tonic has about 600 mg sodium per liter, more than most store drinks. The culture eats most of the 12 g of sugar per liter, so what's left is tart, not syrupy.
Live cultures
The sauerkraut brine brings lactic-acid bacteria, the same family found in yogurt and kefir. In a 2021 Stanford study, people who ate more fermented foods had a more diverse gut microbiome and lower inflammation markers.
You control every ingredient
Nothing goes in except tea, sugar, salt, vinegar and fruit. No dyes or sweeteners. Change the salt for hot days or the caffeine for evening sessions.
Cheap, and it uses scraps
A liter costs about 20–30 cents in tea bags, sugar, salt and vinegar. The flavor comes from peels you'd otherwise throw away.
Per liter
Wild Peel Tonic
Typical store sports drink
Water
Sodium
~600 mg
~450 mg
almost none
Sugar
under 12 g
~55–60 g
0 g
Live cultures
Yes
No
No
Fizz
Natural
Usually flat
None
Cost
~$0.25
~$2–4
~$0
It's a home ferment, so it varies from batch to batch and the numbers here are estimates. For sessions longer than 90 minutes you also need carbs, so pair it with fruit or the Recovery Lassi.
Equipment
What you need
Brewing
5 L protein-powder jar, washed well. Replace it once the inside is scratched or cloudy.
Fine strainer and a funnel
Long spoon or tongs used only for the brew
Small pot or kettle for the tea concentrate
Bottling
Plastic soda bottles, 500 mL–1 L. Bottles made for fizzy drinks handle pressure better than thin water bottles.
A small jar of red-cabbage test liquid (see pH test)
Make the starter culture
Fermented cabbage
The brine from homemade sauerkraut starts the tonic and recharges it later. You need 500 mL to start and about 150 mL now and then. Choose the quick juice if you want brine in a few days, or full sauerkraut for brine and a side dish.
3–5 days · all liquid
Quick cabbage juice
3 cupschopped green cabbage (about 300 g)
1 Lwater
1½ tspsalt (about 9 g)
Pulse everything in a blender for a few seconds until the cabbage is in small bits, not a smooth purée.
Pour it into a clean jar and leave 3 cm of space at the top. Put the lid on loosely.
Leave it at room temperature for 3–5 days and stir once a day.
It's ready when it smells sour and pickle-like and turns the test liquid pink. Strain it, then keep the juice in the fridge for up to a month.
1–4 weeks · brine + sauerkraut
Classic sauerkraut
1 kggreen cabbage (1 medium head)
20 gsalt, 2% of the cabbage weight (about 1 heaped tbsp)
500 mLextra 2% brine: 10 g salt dissolved in 500 mL water. This gives you more liquid for the tonic.
Take off 2 clean outer leaves and set them aside. Quarter the cabbage, cut out the core and slice it thin.
Sprinkle on the salt and squeeze and massage it with your hands for 5–10 minutes, until it's limp and sitting in its own juice.
Pack it tightly into a jar and press it down hard. Pour in the juice from the bowl and the extra brine.
Cover the top with the saved leaves and weigh them down with a small water-filled jar or a zip bag of brine. Everything must stay under the liquid.
Put the lid on loosely and keep the jar at 18–22 °C out of the sun. Press it down every day for the first few days.
Taste it after 1 week. When it's pleasantly sour, pour off the brine for the tonic and move the sauerkraut to the fridge to eat.
Tips. Use plain salt without iodine if you can find it, since iodized salt can make the brine cloudy. Weigh the salt rather than measuring by spoon: too little lets spoilage in, too much stalls the ferment. Red cabbage works too, but it turns the tonic pink and makes the pH test hard to read. Save 150 mL of old brine to start the next jar faster.
Kraut safety: anything above the brine can spoil. If fuzzy or colored mold appears, throw out the jar. A flat white film is kahm yeast: skim it off and push the cabbage back under the brine.
Day 0 · once
Starter batch (4 liters)
3.5 Lwater
7 bagsblack tea
4 tbspwhite sugar (about 50 g)
500 mLlive cabbage brine, from homemade sauerkraut or refrigerated unpasteurized sauerkraut. Shelf-stable jars are pasteurized, so the bacteria in them are dead.
No extra salt in the starter. The brine provides about 1 g of sodium per liter at the start, and this settles to about 600 mg once the daily feeds take over.
Make a concentrate. Steep the tea bags in 1 L of boiling water for 5–10 minutes. Remove the bags and stir in the sugar until it dissolves.
Cool it. Add 2.5 L of cold water. Check the temperature with a clean finger. It should feel cool or barely lukewarm, below 30 °C, because heat kills the culture.
Start the culture. Pour everything into the jar: tea, brine, vinegar and peels.
Loose lid. Screw the lid on, then back it off a quarter turn so gas can escape. Keep it out of the sun, ideally at 20–26 °C.
Wait 2–4 days. It's ready when it tastes clearly tart, about like lemonade, and turns the test liquid pink. Small bubbles and cloudiness are normal. Then start the daily cycle.
Every day
The daily cycle
Taste and test. The brew should taste tart and turn the test liquid pink. If it's purple, skip today's harvest and see Troubleshooting.
Harvest 1 L. Pour it through the strainer with clean hands and a clean funnel.
Bottle it. Leave about 6 cm (2.5 in) of headspace. Add bottle add-ins if you like. For more fizz, add ½ tsp sugar per 500 mL.
Feed the jar right away using the amounts below.
Squeeze and chill. Cap the bottles tight and leave them on the counter. Squeeze them a few times a day. Move them to the fridge when they feel firm with only slight give, usually after 12–36 hours. Drink within a week and open slowly over the sink.
Daily feed
Steep the tea bags in the hot water for 5 minutes, then stir in the sugar and salt. Remove the bags and add the cold water. The mix is cool enough to pour in right away. Use 2 tbsp of vinegar per liter if the brew tasted flat or the test looked purple.
Every 4–7 days
Swap the peels
Remove soft or pale peels with the clean spoon and add fresh ones. Take pineapple skins out after 3 days because they ferment strongly.
When it slows
Add more brine
If bottles take more than 48 hours to firm up, stir in 100–150 mL of fresh cabbage brine.
Monthly
Reset the jar
Save 1 L of brew. Wash the jar with hot soapy water and rinse it well. Restart with the saved liter plus 3 L of fresh sweet tea, 2 tbsp vinegar, ½ tsp salt and fresh peels.
Going away
Pause it
Feed it, tighten the lid and put the jar in the fridge for up to 2 weeks. Let it warm up for a day before your next harvest.
Flavor menu
Choose your peels
Peels in the jar carry wild yeast and set the base flavor. Bottle add-ins go into each bottle and give a fresher taste and extra fizz. Put fresh herbs in bottles only, because they rot in the jar.
Citrus Classic
fizz ●●○○
Jar
1–2 mandarin or orange peels, 3 lemon zest strips (no white pith)
Bottle
Squeeze of lemon
Orchard
fizz ●●●○
Jar
Peel and core of 1 apple, 1 cinnamon stick
Bottle
1 tbsp apple juice
Tepache
fizz ●●●●
Jar
Skin of ¼ pineapple, 1 clove, 3 slices of ginger. Take the skin out after 3 days.
Bottle
1 tbsp pineapple juice
Ginger Zinger
fizz ●●●○
Jar
5 thin coins of fresh ginger, 2 lemon zest strips
Bottle
1 extra ginger slice, ½ tsp honey. Easy on the stomach during training.
Garden Cooler
fizz ●●○○
Jar
Lime zest strips, peel of ½ cucumber
Bottle
3 mint leaves, 2 cucumber slices
Berry Red
fizz ●●●○
Jar
A handful of red grapes, lightly crushed, or apple peel
Bottle
3 frozen berries or a pinch of dried hibiscus. Keep hibiscus out of the jar, because its red color ruins the pH test.
Pear & Spice
fizz ●●○○
Jar
Peel of 1–2 pears, 2 cardamom pods, cracked
Bottle
Small pinch of cinnamon
Tropical
fizz ●●○○
Jar
Mango peel, 1 mandarin peel, lemon zest
Bottle
1 tbsp mango purée
Mango skin contains urushiol, the irritant in poison ivy. Skip it if mango skin or poison ivy makes your skin react.
Keep these out of the jar: moldy or bruised fruit, waxed citrus unless scrubbed in hot water (buy organic if you can), crushed fruit pits or seeds, rhubarb leaves, and anything sprayed or from the roadside.
Swaps
Tea, sugar and electrolyte options
Ingredient
Option
How to use it
Tea
Black (default)
Tea feeds the microbes and gives the drink body. 2 bags per liter is about 80–100 mg caffeine, the same as 2 cups of tea.
Green
Lighter and grassier. Use the same amount.
Rooibos
Caffeine-free, for evening training. Keep at least 1 black or green bag per liter so the culture gets enough nutrients.
Sugar
White (default)
Cleanest taste and ferments most predictably.
Brown or raw cane
Caramel flavor and trace minerals. Use the same amount.
Honey
Use 1 tbsp in place of 1 tbsp sugar. Raw honey ferments more slowly.
Fruit juice
100 mL apple or grape juice replaces about 1 tbsp sugar.
Blackstrap molasses
No more than 1 tsp per liter. Strong flavor, but it adds potassium.
Sodium
Salt ¼ tsp/L (default)
About 590 mg sodium per liter, inside the usual sports-drink range of 460–1150 mg/L. Use up to ½ tsp on very hot days or if you sweat heavily.
Potassium
Coconut water
Use 200 mL in place of water at bottling (not in the jar) for about +450 mg potassium. It also adds fizz.
Salt substitute (KCl)
A pinch, no more than ⅛ tsp per liter, gives about +400 mg potassium. Skip it if you have kidney problems or take blood-pressure medication.
Magnesium
Skip
You get enough from food. Epsom salt works as a laxative, so keep it out.
Your question
Should I add brewer's yeast?
Not as a regular step. The fruit skins already carry wild yeast. Here's what each kind of yeast does:
Won't ferment
Brewer's / nutritional yeast flakes
The yeast is dead. It adds B vitamins and a savory yeasty taste but no fizz. If you want the nutrition, stir it into food.
Avoid in the jar
Active dry, baker's or beer yeast
It crowds out the wild culture. The brew turns beery and less sour, makes more alcohol, and bottles can turn hard in a few hours.
Better boost
Fresh skins, brine, warmth
Apple, grape and pineapple skins are full of wild yeast. Add fresh brine and move the jar somewhere at 24–26 °C.
Only use it as a rescue. If bottles won't firm up after 3 days somewhere warm, add 3–4 grains of dry yeast to one bottle and check it every 2–3 hours. About alcohol: wild fermentation always makes a little. Fresh harvests usually stay under about 1%, but bottles left warm for a long time get stronger.
Kefir pairings
Kefir sports drinks
Salted fermented-milk drinks like ayran and doogh are traditional thirst quenchers. Kefir plus your tonic makes a tangy, fizzy recovery drink with protein.
Two rules: Keep kefir and kefir grains out of the jar. Milk grains need milk, and dairy spoils a perpetual brew. Mix in the glass and drink the same day. Never seal kefir mixes in a bottle to build fizz.
Post-workout
Classic Ayran
Mix
250 mL kefir, 200 mL cold water or flat tonic, ⅛ tsp salt, 4 mint leaves
How
Shake or blend until frothy
~9 g protein · ~400 mg sodium
Post-workout
Fizzy Doogh
Mix
250 mL kefir, 250 mL chilled fizzy tonic (Citrus or Ginger works best), pinch of dried mint, pinch of salt
How
Pour the tonic slowly into the kefir, because it foams a lot
Light and sparkling
Long sessions
Recovery Lassi
Mix
250 mL kefir, 150 mL tonic, ½ banana or a handful of berries, 1 tsp honey
How
Blend
More carbs for refueling
Kefir whey as a starter
No sauerkraut? Strain kefir through a cloth in the fridge overnight. Use 250 mL of the yellowish whey in place of the 500 mL cabbage brine, and add 1 tsp of salt to the starter batch, since whey has no salt. The thick part left in the cloth is kefir cheese.
Drinking it
Training plan
When
What
How much
30 min before
Tonic, chilled
200–300 mL
During
Tonic. Leave dairy out during hard efforts.
150–250 mL every 15–20 min in sessions over 45 min
Within 1 hour after
Ayran, Doogh or Lassi
One glass, about 450–500 mL
Hot days
Tonic with ½ tsp salt per liter
Drink to thirst
Check with a doctor first if you're pregnant, immunocompromised, on a low-sodium diet, have kidney disease, or take blood-pressure medication.
No strips needed
Red-cabbage pH test
Red cabbage juice changes color with acidity. Low pH is what keeps a wild ferment safe.
Make the indicator. Chop 2–3 red cabbage leaves and pour a cup of boiling water over them. After 10 minutes, strain the purple liquid into a jar. It keeps about a week in the fridge.
Set up references. In three white cups, add 1 tbsp water, 1 tbsp vinegar and 1 tbsp of your brew.
Add 1 tbsp of indicator to each cup and compare. Your brew should look close to the vinegar cup and clearly different from the water cup.