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Brewfecto

coffee & tea calculator
with brewing notes.

1) Select brew type

Cold brew

Pour over

2) Set dosage

weight
icon of needle and tick marks on a scale dialbiceps strength iconmeasuring cup with coffee beans icon
grams
plant ingredient icon
 g1:
sifted

fl oz
ml

water droplet icon
 g
ratio
15 strong
18 med
20 weak
Yield
steaming mug icon
3

fl oz
ml, l

A
Coffee:30 g1/3 cup
Water510 g2 cups

dose instructions

Go by the Volume column on the right if you don’t use a scale or to picture how much brew this is. Grams measurement is precise, volume rough.
Press the big up and down arrows on the right to increase or decrease your water in half-cup steps. It keeps the brew strength set by the brew ratio input.
Change the roast setting in the upper right to French roast if that is what you are using to get a more accurate volume measure of coffee beans.
If you are entering grams and getting annoyed, turn off the lock ratio check box. It’s meant for keeping the brew ratio when you scale up or down.
To convert a brew ratio from grams/liter to the gram/grams used here, uncheck the lock ratio check box, enter 1000 for water, your grams of coffee, then check the lock ratio check box.
If you make loose leaf tea, use a scale with .1 gram accuracy rather than the .5 gram accuracy scale recommended for pour over coffee.
To finish off a bag of coffee and get the brew to be your preferred strength:

❑ set the water brew ratio you like
✔ check the lock ratio box
⬇ press the big up and down arrows on the right till the light brown coffee line with the coffee bean icon bean matches what is left in the bag
💧 use the calculated amount of water

Save and Start over buttons

If you press the Save button your browser or app will remember the current brew type’s dosage and entries you’ve made in the 3) Brew notes section.
Saving also copies your dosage settings to the clipboard in a format that can be pasted into a spreadsheet. Commenting in a spreadsheet on the brew that resulted from various settings helps keep you from going in circles trying to pinpoint your favorite strength and yield.
Press the “Start over” button to forget your last trial for that brew type and return to the default dosage suggestion.

iced

Japanese-style iced filter coffee recipe Flash-brew Aeropress iced coffee recipe Flash chilled iced tea recipe

icon

ingredient

grams

volume
Hot brew a concentrate

coffee bean icon

ground coffee

9 g

⅓ cup

🔥 🫧 🫧

hot water
99 g
1 cup

onto

🧊
ice (7 cubes?)
70 g

⅔ cup

customize recipe
Change the proportion of ice with the percentage below:
Split the Water
heat
state 🌡️
plan grams
g beans∶
water
hot 🔥
300g
320g
60 %
1∶ 9
ice
8
❆️
🧊
s
200
g
%
30–45 %
1∶ 6
Total
500 g
100 %
1∶ 15
❆️: g
♙
♙
Change the brew strength with the brew ratio term below:
Iced Dosage
grams

volume
beans
30
1∶
from
2) Set dosage
total
water

500 g

14 strong
15 med
16 weak
or
cups
fl oz
~92% of your hot brew
ratio term, so 1∶15

To scale the batch size: In the “2) Set dosage” section change the amount of ground coffee to use.

Save your settings in the “2) Set dosage” toggle above using the Save button.

Flash chill is a variation on hot brew made a bit stronger to make up for additional ice melting as it keeps the final drink cool. Take the water that would have been used for hot brew and split it between hot and ice then brew a hot concentrate onto ice cubes.

Intensify the hot concentrate by grinding finer and brewing longer than your usual for hot brew.

The default ice percentage and brew ratio match Crema Coffee’s Iced Aeropress Brewing Guide.

James Hoffmann’s iced filter coffee video informed this flash chill calculator.

Cool the hot brew with the ice before pouring it into ordinary glass. Hot brew may shatter it.

Freeze a few cubes of brew to top off the next day’s finished flash chill so melting ice doesn’t dilute your drink.

caffeine

99 milligrams

Caffeine released
over tea infusion time
steep

caffeine released

minutes

pct

middle

range
5 min

69%

19 mg

28-9 mg

10 min

92%

39 mg

48-9 mg

15 min

100%

59 mg

68-9 mg
A heaping chashaku scoop is about 1 gram or ⅓ teaspoon. Two scoops is a typical serving.

Up to 400 mg of caffeine per day is a safe intake for most healthy adults, according to the US Food & Drug Administration (FDA) and the European Food Safety Authority (EFSA). Up to 200 mg for pregnant women, much less for children. Some people have a lower tolerance.

Basis for this caffeine estimate:

An experiment on one roasted batch of Arabica coffee beans found that a V60 extracted 10.19 ± 0.97 an Aeropress extracted 10.14 ± 1.21 a French press extracted 6.89 ± 1.00 mg caffeine /g coffee beans.
± is one standard deviation. (Angeloni, Giulia et al, 2019)

An experiment (Angeloni, Giulia et al, 2018) on one roasted batch of Arabica coffee beans measured:

⬢ A 6.5-hour refrigerator immersion cold brew extracted 8.93 mg caffeine / 1 g beans. The longer brew time recommended in this calculator will extract more caffeine, so estimating 10 mg caffeine / 1 g beans.

⬢ A 6.5-hour room temperature slow drip extracted 12.67 mg caffeine / 1 g beans. The shorter brew period recommended by home slow drip brewer manufacturers will extract less caffeine, so estimating 12 mg caffeine / 1 g beans.

Depending on the origin and growing conditions of the coffee beans, caffeine content can vary by almost a factor of 2, so your brew may be higher or lower than this estimate range. This brewing technique extracts less than half the total amount of caffeine in the beans. “Mean caffeine content in ground coffees was 19.3 mg/g (sd = 2.7, ranging from 13.0 to 23.1 mg/g)” (Sanchez, 2017)

“Robusta contains about 1.4 to 1.8 times more caffeine” (Olechno, Ewa et al, 2021) than Arabica beans. Grocery store commodity coffee packaging that doesn’t use the word “Arabica” on the front, as the only ingredient, or somewhere in the description may be a blend of the two or entirely Robusta. Specialty coffee is usually Arabica and often doesn’t state it on the packaging. The word “strong” on the packaging implies Robusta is present.

If the roaster selected Arabica beans with high caffeine content and blended them with Robusta, the caffeine in your brew may be twice as high as the estimate shown above. What do you have, a death wish?

References:

Angeloni, Giulia et al. “What kind of coffee do you drink? An investigation on effects of eight different extraction methods.” Food research international (Ottawa, Ont.) vol. 116 (2019): 1327-1335. doi:10.1016/j.foodres.2018.10.022
Angeloni, Giulia et al. “Characterization and comparison of cold brew and cold drip coffee extraction methods.” Journal of the science of food and agriculture vol. 99,1 (2019): 391-399. doi:10.1002/jsfa.9200

Olechno, Ewa et al. “Influence of Various Factors on Caffeine Content in Coffee Brews.” Foods (Basel, Switzerland) vol. 10,6 1208. 27 May. 2021, doi:10.3390/foods10061208

Sanchez, Juan M. “Methylxanthine Content in Commonly Consumed Foods in Spain and Determination of Its Intake during Consumption.” Foods (Basel, Switzerland) vol. 6,12 109. 4 Dec. 2017, doi:10.3390/foods6120109

Per gram of instant coffee has “mean caffeine content of 35.7 mg/g (sd = 6.9, ranging from 18.0 to 43.8 mg/g)” (Sanchez, 2017) This was multiplied times the number of grams of instant crystals in your dosage.

Reference:

Sanchez, Juan M. “Methylxanthine Content in Commonly Consumed Foods in Spain and Determination of Its Intake during Consumption.” Foods (Basel, Switzerland) vol. 6,12 109. 4 Dec. 2017, doi:10.3390/foods6120109

Tea leaves range in caffeine content, around 17–37 mg caffeine/ g leaves. (Sanchez, 2017), (Boros et al, 2016), (Hicks et al, 1996). This was multiplied times the number of grams of tea leaves in your dosage and corresponds with the 100% line in the caffeine release table.

It takes serial infusions to extract all the caffeine in tea leaves. 5 minutes of hot infusion extracts about 69% of the caffeine, 10 minutes 92%, 15 minutes 100%. (Hicks et al, 1996)

An experiment using immersion brewing in a refrigerator for 12 hours found that a green tea yielded 17 mg caffeine per 1 gram of tea leaves, oolong 13 mg, black 8 mg. (Lantano et al, 2015) This was multiplied times the number of grams of tea leaves in your dosage to provide a caffeine estimate.

Tea leaves range in caffeine content, around 17–37 mg caffeine/ g leaves. (Sanchez, 2017), (Boros et al, 2016), (Hicks et al, 1996). So your brew’s caffeine may be twice the estimated amount.

References:

Lantano, Claudia et al. “Effects of alternative steeping methods on composition, antioxidant property and colour of green, black and oolong tea infusions.” Journal of food science and technology vol. 52,12 (2015): 8276-83. doi:10.1007/s13197-015-1971-4

Sanchez, Juan M. “Methylxanthine Content in Commonly Consumed Foods in Spain and Determination of Its Intake during Consumption.” Foods (Basel, Switzerland) vol. 6,12 109. 4 Dec. 2017, doi:10.3390/foods6120109

Monique B. Hicks, Y-H.Peggy Hsieh, Leonard N. Bell, Tea preparation and its influence on methylxanthine concentration, Food Research International, Volume 29, Issues 3–4, 1996, Pages 325-330, ISSN 0963-9969, https://doi.org/10.1016/0963-9969(96)00038-5. (https://www.sciencedirect.com/science/article/pii/0963996996000385)

Boros, Klára et al. “Theanine and Caffeine Content of Infusions Prepared from Commercial Tea Samples.” Pharmacognosy magazine vol. 12,45 (2016): 75-9. doi:10.4103/0973-1296.176061

Caffeine content per g of matcha is “between 18.9 and 44.4 mg/g” (Kochman et al, 2020) This was multiplied times the number of grams of matcha in your dosage.

Reference:

Kochman, Joanna et al. “Health Benefits and Chemical Composition of Matcha Green Tea: A Review.” Molecules (Basel, Switzerland) vol. 26,1 85. 27 Dec. 2020, doi:10.3390/molecules26010085

caffeine molecule icon

3) Brew

pour timeline

start

target

description

0:00

19 g

Pour 0: pre-wet

0:19

199 g

Pour 1
pour 1 warning

1:29

299 g

Pour 2

1:39

399 g

Pour 3

1:49

499 g

Pour 4

1:59

599 g

Pour 5

1:69

699 g

 Pour 6

timer

0 g
0:00
: 

presets


more

Pre-wet and 1 pour
❯
Chemex
❮
George Howell
3 cup
6 cup for 1
6 cup for 2
3 and 6 cup above are names of Chemex brewer models
∞

customize recipe

Pre-wet, bloom

2–3X the weight of the grounds

:30–45

Pours

1–6.

% of all water
0 blank: all equal pours

% of all water
0 blank: equal remaining pours

seconds to complete a pour

seconds between pour start 1 and 2

seconds between pour starts

pour instructions

The presets set up the timer to apply the pour over recipes from some top brewers to your dosage.
It is easier to brew these recipes with a grams scale and a gooseneck kettle, but you can ballpark it.
Search on the names on the preset buttons for crucial tips. That is, Tetsu Kasuya, James Hoffmann, George Howell, and Blue Bottle Coffee.
After the optional pre-wet keep your slurry at least soaked enough for brew to continue dripping out the bottom. For three or more pours, Pour 2 on should match the grounds’ high tide from the previous pour. You may need to start pouring earlier or later than the timeline start time says. You can align the timeline with your scenario by opening the “customize recipe” toggle above and changing the “Wait” settings by 15–30 seconds.
Factors that affect pour over drain time ⏱️

️
🐇
low wait
🐢
high wait
Brewer drain hole size
one large, e.g. Hario or Chemex
many small, e.g. Kalita Wave
Dosage size
small, e.g. 300g single mug
large, e.g. 900g Chemex
Roast
dark

light

Grind
coarse

fine

Save and Reset buttons

You can have your browser or app remember to use the recipe on the screen by opening the “customize recipe” toggle and pressing the Save button at the bottom of it.
Saving also copies your recipe settings to the clipboard in a format that can be pasted into a spreadsheet.
Press the “Reset” button at the bottom of the “customize recipe” toggle to clear out your recipe experiment and return to the default.

tea bag conversion

Enter numbers from your package of tea bags to see dosage grams as how many tea bags. Left blank it assumes 2g per tea bag, a frequent measure for one serving.
Example package label
grams in 1 tea bag
Your tea package
g
1.9
Your dosage
9

99

9
Tea bags contain pieces and dust of leaves which brew faster and stronger than the same gram weight in whole loose leaf tea. For comparable strength:
water droplet icon
water brew ratio term number
🕰️
brew time
tea bags
➤
bigger term
(e.g. 1∶120)
or
⇩
less time (e.g. 4)
loose leaf
⇩
smaller term
(1∶100)
➤
more time (5)
tea bag icon

notes

Immersion

Grind:
resemblance: salt
description: medium to coarse
measure: 809 to 909 µm
A shorter brew time will taste better using a finer grind; a longer brew time with a coarser grind. Factors that shorten brew time are a V60 dripper (big drain hole) or 1–2 pours. Longer brew times result from drippers with small drain holes or 4+ pours.
Brew
time:
9 minutes
Estimate for current recipe is 1:19
Roast:dark
Temperature
Water:209°F / 99°C
Brew:199℉ / 94℃
Your water should be 6-8°F / 3-4°C higher than your target brewing temperature, says Scott Rao.
Instant made from boiling water in an insulated mug will burn your mouth for hours. Showing a drinkable temperature.

Turn cold brew into nitro brew with a nitro dispenser.

Slow drip

💧
Slow drip coffee brewing requires special equipment which stacks or suspends parts by tower. Go by the brewer manufacturer's instructions, which are approximately:
Brew
ratio:
1: 10 strong
1: 12 medium
1: 13 weak
Grind:
resemblance: sand
description: medium
measure: 800 to 1000 µm
Tower brewers broaden the grind range to that of hot pour over.
Brew
time:
3–8 hours, depending on the slow drip brewer, drip rate, and grams of water used
Roast:medium or light
Drip
rate:
About 1 drip per second (60 drips / minute).
40 drips / minute for a light roast
80 drips / minute for a dark roast
Some manufacturers suggest 120 drips / minute, others say that results in brew that is too weak when using their brewer.
A lower water brew ratio term such as 10, fine grind and slow drip rate will result in strong brew.
A higher water brew ratio term such as 12, medium grind and fast drip rate will result in weaker brew.
💡
🧊

Pour over and Aeropress have an "iced" section below "2) Set dosage" with a recipe for flash chilling hot brew into a cold drink. Spider charts illustrate differences between cold and hot brew. In it CB is cold brew, P pour over.

🏔️

Tea collection:

Immersion

◈
refrigerator

h - hours of immersion brewing in a refrigerator

1:ratio - suggested grams of water to use per 1 gram of dry loose tea leaves to result in a medium-strength brew. Adjust for variety within the tea type and personal taste.

Teasenz - immersion cold brewing starting point recommendations from experts at the online Chinese tea shop

Information from the table above is transformed in a multi-line chart below.
multiple line graph of medium strength cold brew tea, brew ratio by hours
The colored curved lines in the chart above illustrate:
  1. Black (oxidized) tea releases more flavor than green (unoxidized) tea so may need twice as much water to get to medium strength.
  2. Green tea continues releasing flavor after the 5th hour of cold immersion, whereas black tea doesn't have much flavor left.
Your tea's line may be above or below the examples shown and flatten early or late. Use these brew ratio by brew hours recommendations as a starting point.
Arrows in the upper and lower left corners of the chart show that to weaken the tea strength, increase the water brew ratio term (1:nnn). To strengthen, decrease it. Increasing the brew hours can strengthen the tea as long as it is in the range of hours where flavor can still be extracted.
― ―
Decrease the water brew ratio term if you dilute your brew with ice or milk. Increase the term if you use tea bags.
To fine-tune your brew strength by brew ratio when using a single gram of leaves you need a scale that reads to 0.1 grams.
◈
Immersion
🌞
sun tea and room temperature
Brew
time:
2–4 hours in the sun. Refrigerate immediately.
⚠ Brewing by the sun's warmth on a hot day puts your brew in a foodborne illness danger zone, like any other perishable food left out. Toxin-producing bacteria may take hold. Refrigerator cold brew and hot brew are safe.
If you're making sun tea anyway and prefer counting in tea bags to grams and brew ratios, a common sun tea recipe is 8 tea bags per gallon (which is brew ratio 1∶250). Specialty tea shops counter with 4 tea bags per gallon.
Multiply the refrigerator cold brew hours above × 0.7 to get the approximate brew hours at room temperature. For example, compared to a tea brewed in the refrigerator for 5 hours, brewing at room temperature for the same brew ratio for 3.5 hours will obtain about the same strength.
🌞

Slow drip

💧
Slow drip tea brewing requires special equipment which stacks or suspends parts by tower. It brews a more distinctive flavor than immersion.
A Bruer Cold Drip System set to the baseline drip rate for coffee (60 drips per minute) at full water capacity (700 grams) brewed medium strength tea at the brew ratios:
green1∶70
black1∶60
The volume of the bed of tea leaves used in slow drip is less than half that for coffee. Brew at maximum capacity to use maximum leaves. Soak the tea leaves in 4× their weight in water to plump them up prior to placing in the drip brewer.
A 2 1/2" metal Bruer Filter & Dispersion Disk or Able DISK filter between the paper filter and the leaves will keep the paper from conforming to the shapes of the leaves beneath it, which creates channels for the water to run off the edges and bypass percolation.
💧

Brew time: 3 minutes

Gong Fu Cha style: tea leaves and a gaiwan brewer from a tea shop, 1:20 brew ratio, 100 g water, temperature as above, 10 second steep at first plus another 10 seconds each infusion, 5–20 infusions.
sun icon with rays

Calculator overview

This site contains affiliate links to products. We may receive a commission for purchases made through these links.

The Brewfecto coffee and tea calculator helps you pinpoint your favorite amount and strength of coffee and tea.

For each brew type in section 1), you can save your preferred dosage for that type in section 2), and reminder notes appear in section 3) about things like brew time and temperature.

For the pour over brew type, special settings appear for several well-known techniques which will be applied to the dosage you set in section 2). You can customize and save these settings.

All brew types here are manual, meaning the brewers do not use electric power. Heat the water by using electricity at home. Heat water by gas or fire when there is no power, such as during a power outage, off-grid at home, or when dry camping. If you intend to brew coffee without electricity and grind the beans yourself, your grinder must be a hand grinder, not electric.

You can save this calculator to your device for use without an internet connection. This website is installable for free as a Progressive Web App (PWA), which launches to this website’s listing of blog posts. A launcher straight to Brewfecto is available as a paid app on Google Play and Amazon Appstore.

Get it on Google Play
Amazon Appstore
Google Play and the Google Play logo are trademarks of Google LLC.

Making coffee in a power outage

If you are in a power blackout and don’t have a manual brewer…

Drip machine pour over recipe

If you can boil water and have a drip machine, it uses the pour over technique which is percolation. Pull out the carafe and basket and proceed if you can align the holes in the basket bottom and carafe top so that the brew will drip through.
• Place your usual filter and amount of grounds in the basket.
• Boil your usual amount of brewing water and wait 30 seconds for it to cool a little.
• Place the carafe in the sink in case this spills, and the basket on the carafe, aligning the drain of the basket with the hole in the top of the carafe. Have mugs ready to catch the brew in case it spills.
• Slowly pour the water in circles onto the grounds in the basket. It’s done when it stops dripping.

🔥♨🔥

Hot immersion recipe

If you can boil water and don’t have a drip machine, brew by immersion. These instructions are for brewing with a US cup of water and little equipment. If you want to scale up, above in 1) brew type pick French press and in 2) dosage set it to the water amount you want to use. A brewing vessel with a spout won’t spill and will thereby yield more brew when pouring off in the final step than a vessel without a spout.
• Get two mugs. Fill one with water to the rim. Pour the water into a 3rd container.
• Measure 3 Tablespoons coffee grounds.
• Boil less than a cup of water and split it between the two empty mugs to preheat them. Cover them to keep in the heat.
• Boil the water you set aside in the 3rd container.
• When the water reaches a rolling boil, remove it from the heat.
• Empty the heating water from Brewer Mug A. Add the coffee grounds.
• Set and start a timer for 4 minutes. Immerse the grounds with the hot water almost to the mug’s rim. Cover the brew to keep the heat in. One minute in, stir to break up and sink the floating grounds.
• After 4 minutes, empty the heating water from Drinking Mug B. Put the mug in the sink. Prop a sieve on it if you have one. Dribble the brew in Brewer Mug A into Drinking Mug B, blocking grounds with a tablespoon as best you can. Stop when what is coming out of Brewer Mug A looks more like mud than gritty brew.
• Dispose of the spent grounds in the compost or a tub in the trash. Grounds will clog your pipes and leak in the trash all day.

⚠ Don’t use untempered glass such as a jar for hot brew. It can shatter from thermal shock. Borosilicate glass such as Pyrex is fine for hot brew.

🫙 🕰️ 🕰️ 🕰️

Cold immersion recipe

If you can’t heat water, make cold brew by immersing grounds for 12 hours at room temperature. Don’t make more than you need for one morning as it goes bad in a day without refrigeration. Cold brewing in a liquid measuring cup with a spout eases pouring off the brew when it’s done.
• Put 1/3 cup coffee grounds in your brewing vessel. Add 1 cup of water. Stir and cover. If you want to scale up, on this page in section 1) Select brew type, pick Cold brew Coffee and in 2) Set dosage, set the ratio to 8.
• Wait 12 hours. Stir now and then to break apart the grounds floating and at the bottom.
• The next day place a mug in the sink. If available place a coffee filter in a sieve or the basket from a drip machine on the mug. Pour from the brew vessel into the makeshift filter over the mug. Filter or not, pour slowly and try with a tablespoon to block the grounds in the brewer from leaving the brewer.
• Add water if it’s too strong.
℧
dancing goat portrait in coffee bean locket

Long ago, Ethiopian goats danced how fine it is to eat coffee cherries enough times without dying for their shepherd Kaldi to meet the muse.

flying insect