The Blending School

Everything about whiskey blending, free

42 guides and 5 calculators. The library is a bottle: each band is a subject, and the bottle fills from the surface down, starting-out at the top, the deep tradition at the bottom. Tap a band to open it, or search everything.

Calculators5 TOOLS
Blend Proof Calculator
Enter what is going into the glass or bottle.
Whiskey Dilution Calculator
Water is the one ingredient with a proof of zero, which makes its math exact.
Headroom Calculator
Not 'what will the proof be' but 'how much can I pour before I cross my line.
Proof to ABV Converter
In the United States, proof is exactly double ABV.
Bottle Split Calculator
Splitting a bottle produces two bottles at the same proof with proportional shares of every component.
Starting out6 GUIDES
Already have a bottle? How to adopt it into the app
You do not need to start over to track an existing infinity bottle. How to take a best-guess snapshot of a mid-life bottle and run the books forward.
Choosing your first three whiskeys
The founding pours set an infinity bottle's opening character. A simple framework for picking the first three whiskeys, with combinations that work.
How to start an infinity bottle this weekend
Starting an infinity bottle takes one clean bottle, two or three whiskeys you like, and a record of what went in. A complete first-day walkthrough.
House rules: what goes in, what never does
Every infinity bottle needs house rules. The common ones keepers adopt, the reasoning behind them, and the freedom to break them on purpose.
Decanter, bottle, or barrel: what to blend in
Glass bottle, crystal decanter, or mini oak barrel for an infinity bottle? The honest tradeoffs of each vessel, and the one thing that actually matters.
What is an infinity bottle?
An infinity bottle is an ongoing personal whiskey blend that never empties. Here is how it works, why people keep one, and what it slowly becomes.
The math5 GUIDES
How to calculate the proof of a whiskey blend
Blend proof is a volume-weighted average: multiply each whiskey's volume by its proof, add them up, divide by total volume. Worked examples included.
Adding water: dilution math that round-trips
How to calculate exactly how much water brings a whiskey blend to a target proof, using V1P1 = V2P2, plus why a few drops change more than flavor.
Headroom: staying under your target proof
How much barrel-proof whiskey can you add before the blend crosses your target? The headroom calculation, derived and worked through.
Mash bills: what's published, what's a guess
Some distilleries publish exact mash bills, many never do. How mash bill data really works, and how to compute a blended mash bill honestly.
The Ship of Theseus, measured in ounces
If you replace every plank of a ship, is it the same ship? An infinity bottle lives the old paradox, and the survival math can actually be computed.
Blending at home8 GUIDES
How to blend whiskey at home: the complete guide
A start-to-finish guide to blending whiskey at home: picking components, ratios, proof math, resting the blend, and keeping records that let you repeat it.
Blending bourbon and rye: ratios that work
Practical starting ratios for blending bourbon with rye at home, what each proportion does to the palate, and how to adjust from there.
Fixing a blend that went wrong
Too hot, too sweet, too flat, too smoky: how to diagnose what is wrong with a whiskey blend and the specific correction for each problem.
Finishing at home: staves, chips, and why mini barrels lie
Adding oak, staves, or a second cask influence to whiskey at home: what works, what does not, and why small barrels over-oak in weeks.
Vatting your own single malts
How to blend Scotch single malts at home: pairing regions, handling peat, proportions, and why a home vatted malt often beats its parts.
Building a blend for a specific palate
How to design a whiskey blend around what a particular person likes: mapping preferences to components, building toward a target, and testing blind.
Blind tasting your own blends
How to blind taste home whiskey blends honestly: setup, glassware, scoring, and the biases that ruin the result if you skip the blindfold.
Keeping a blending journal, and where paper breaks
What to record when blending whiskey at home, how to structure a blending journal, and the specific point where a notebook stops working.
Inside the bottle5 GUIDES
Whiskey does not age in glass, and what changes instead
A sealed bottle of whiskey does not continue aging. What aging really is, why glass stops it, and the slower changes that do happen after opening.
Marrying: why blends improve after they rest
Freshly blended whiskey often tastes disjointed, then knits together over days and weeks. What marrying is, why distilleries build time for it, and how to use it.
Does whiskey oxidize in the bottle?
Open whiskey changes slowly with air exposure. What oxidation actually does to a bottle, how fast, and why an infinity bottle handles it better than most.
Why your proof drifts and what it tells you
An infinity bottle's proof rises and falls with what you feed it. How to read the drift as a record of your habits, and how to steer it on purpose.
Light, heat, and fill level: storing the bottle
Three things degrade stored whiskey: sunlight, heat swings, and excess air. Simple storage rules that keep an infinity bottle healthy for years.
Tasting and collecting5 GUIDES
How to taste whiskey properly
A practical method for tasting whiskey: glassware, the nose, the palate, the finish, and how to build a vocabulary that means something a year later.
Writing tasting notes that mean something a year later
How to write whiskey tasting notes you can actually use later: structure, scoring, recording proof and context, and the notes that turn out to be useless.
Tracking a whiskey collection: what is worth recording
What to actually record about the bottles you own, what to skip, and how collection tracking and blending records overlap.
Storing an open bottle of whiskey
How long open whiskey lasts, what changes it, and simple habits to keep an opened bottle tasting the way it did: fill level, light, heat, and when to decant.
The infinity bottle as a collection strategy
Why an infinity bottle changes how you buy whiskey: fewer dead bottles, better decisions about what to finish, and a permanent record of everything you loved.
Reference5 GUIDES
Bottled-in-bond, cask strength, single barrel: what the label means
The legal and marketing terms on American whiskey labels, decoded: bottled-in-bond, straight, cask strength, barrel proof, single barrel, small batch, and more.
Proof vs ABV: the conversion and where it came from
American proof is exactly double ABV. British proof was different. Here is the conversion, the history, and why blenders should work in one unit and stick to it.
How barrel aging actually works, and why the rickhouse floor matters
What happens to whiskey inside an oak barrel: extraction, oxidation, evaporation, and why barrels on the top floor of a rickhouse age differently from the bottom.
Published mash bills of major American whiskeys
An honest table of American whiskey mash bills: which distilleries publish exact grain recipes, which figures are enthusiast estimates, and which are simply unknown.
The whiskey glossary
45 whiskey terms defined plainly, each linked to a full guide.
Sharing it4 GUIDES
Gifting a pour, with its history attached
Giving a few ounces of your infinity bottle is the best gift in whiskey. How to do it well, and how the blend's data can travel with the liquid.
Serving the house blend to guests
Pouring your infinity bottle for guests: how to present it, the story to tell, guest pour traditions, and making the bottle the best moment of the night.
Splitting a bottle for a second experiment
Splitting an infinity bottle creates a second bottle with the same blend and lineage, free to diverge. When to split, how the math works, and ideas for the child bottle.
Tasting and rating your own blend honestly
How to taste an infinity bottle with a clear head: schedules, side-by-side comparisons, simple ratings, and using notes to learn what you actually like.
The tradition4 GUIDES
Blends that made whiskey history
From Johnnie Walker's grocery-shop origins to Japan's blending houses, the famous blends that shaped whiskey, and what home blenders can steal from them.
Solera: the 200-year-old idea behind your bottle
The solera system, developed for sherry in Spain, is fractional blending across generations. How it works and why an infinity bottle is its home-scale descendant.
Vatting, blending, and why the words matter
Blended whiskey, blended malt, vatting, single barrel: the vocabulary of mixing whiskey has precise meanings. A plain-language tour of the terms.
What is a whiskey thief?
A whiskey thief is the long tube distillers use to draw samples straight from the barrel. How the tool works, its copper history, and why an app is named after it.

Every guide is also in the glossary, 45 terms with one-line definitions.

Reading paths

Start a bottle this weekend

Zero to first pour in an afternoon.

  1. What is an infinity bottle?
  2. How to start an infinity bottle this weekend
  3. Choosing your first three whiskeys
  4. Decanter, bottle, or barrel: what to blend in
  5. House rules: what goes in, what never does

Understand the math

Everything a blender computes, and why.

  1. How to calculate the proof of a whiskey blend
  2. Adding water: dilution math that round-trips
  3. Headroom: staying under your target proof
  4. The Ship of Theseus, measured in ounces
  5. Mash bills: what's published, what's a guess

Become a home blender

Beyond the infinity bottle.

  1. How to blend whiskey at home: the complete guide
  2. Blending bourbon and rye: ratios that work
  3. Fixing a blend that went wrong
  4. Blind tasting your own blends
  5. Keeping a blending journal, and where paper breaks

Read a label like a pro

What the words mean and which ones are marketing.

  1. Bottled-in-bond, cask strength, single barrel: what the label means
  2. Proof vs ABV: the conversion and where it came from
  3. Published mash bills of major American whiskeys
  4. How barrel aging actually works, and why the rickhouse floor matters
  5. The whiskey glossary

Every guide, one list

For when you know what you are looking for.

  1. Already have a bottle? How to adopt it into the app
  2. How to calculate the proof of a whiskey blend
  3. Adding water: dilution math that round-trips
  4. Whiskey does not age in glass, and what changes instead
  5. Blends that made whiskey history
  6. Choosing your first three whiskeys
  7. Gifting a pour, with its history attached
  8. Headroom: staying under your target proof
  9. Serving the house blend to guests
  10. How to start an infinity bottle this weekend
  11. Marrying: why blends improve after they rest
  12. Mash bills: what's published, what's a guess
  13. Does whiskey oxidize in the bottle?
  14. Why your proof drifts and what it tells you
  15. House rules: what goes in, what never does
  16. The Ship of Theseus, measured in ounces
  17. Solera: the 200-year-old idea behind your bottle
  18. Splitting a bottle for a second experiment
  19. Light, heat, and fill level: storing the bottle
  20. Tasting and rating your own blend honestly
  21. Vatting, blending, and why the words matter
  22. Decanter, bottle, or barrel: what to blend in
  23. What is an infinity bottle?
  24. What is a whiskey thief?
  25. How to blend whiskey at home: the complete guide
  26. Blending bourbon and rye: ratios that work
  27. Fixing a blend that went wrong
  28. Finishing at home: staves, chips, and why mini barrels lie
  29. Vatting your own single malts
  30. Building a blend for a specific palate
  31. Blind tasting your own blends
  32. Keeping a blending journal, and where paper breaks
  33. Bottled-in-bond, cask strength, single barrel: what the label means
  34. Proof vs ABV: the conversion and where it came from
  35. How barrel aging actually works, and why the rickhouse floor matters
  36. Published mash bills of major American whiskeys
  37. How to taste whiskey properly
  38. Writing tasting notes that mean something a year later
  39. Tracking a whiskey collection: what is worth recording
  40. Storing an open bottle of whiskey
  41. The infinity bottle as a collection strategy
  42. The whiskey glossary

The app that keeps these books for you

Thief & Blend tracks every pour, runs the proof math live, and remembers how much of the first pour survives. On the App Store for iPhone.

DOWNLOAD FOR iOS