Hop substitution means making one hop stand in for another in a recipe, and the only way it works is if you substitute for two things at once, the bitterness the hop contributes and the flavour and aroma it leaves behind. A hop's bitterness is set mostly by its alpha acid percentage, so equal bitterness means using less of a high-alpha hop than of a low-alpha one, in roughly the inverse proportion. But the aroma is set by the essential oils, and those do not scale with alpha acid at all, so a hop that matches on bitterness can still be a completely different-smelling beer. That gap between the two is where substitution usually goes wrong, because people match the number and then wonder why the beer tastes like the wrong variety. Substituting well means deciding whether you are replacing a hop for its bittering job, for its aroma, or for both, and then doing the arithmetic and the tasting for that specific role. The chemistry that makes one hop behave differently from another is laid out in our piece on the chemistry of hops, and this page is about the practical act of making the swap.
How To Substitute One Hop For Another
- Match the bitterness on alpha acid rather than on weight.
- Scale the weight so a high-alpha hop goes in smaller than the low-alpha hop it replaces.
- Match the aroma by tasting, because the oils do not scale with alpha acid.
- Substitute inside a group for a close match, and across groups only for bitterness.
Match The Bitterness By Alpha Acid, Not By Weight
The first half of a substitution is arithmetic, and it is the part you can get exactly right because alpha acids are measured and printed. Bitterness is produced when the alpha acids in a hop are boiled and isomerized into iso-alpha acids, and the amount of bitterness a given weight of hop contributes is set by how much convertible alpha acid it contains. That is why the alpha acid percentage on a packet is the number that matters and the weight alone is not, and it is why a high-alpha modern hop is dosed in smaller amounts than an old low-alpha continental variety for the same job. So when you replace one hop with another, you are not swapping gram for gram, you are swapping so that the product of weight and alpha acid stays roughly the same, which in plain terms means a high-alpha hop goes in at a smaller weight than the low-alpha hop it replaces. The exact conversion also depends on the batch size, the boil time and the timing of the addition, because a hop added for bittering sits in the boil for an hour and isomerizes far more completely than one added in the last ten minutes, so a bittering substitution and an aroma substitution do not follow the same arithmetic. Two things the alpha acid figure does not capture are how much of that alpha acid is cohumulone, which tends to give a harsher, more clinging bitterness at the same total, and how the hop's form and age have affected it, since old pellets have lost aroma and sometimes potency. The bitterness you land on is a real, measurable match, but a match on that one axis.
Match The Aroma Separately, Because It Does Not Scale
The second half is where substitution earns its name, and the reason it is harder is that aroma and bitterness are almost independent of each other. The essential oils that give a hop its smell, whether citrus, pine, floral, resinous or grassy, are a different set of compounds from the alpha acids, and two hops with identical alpha acid percentages can smell nothing alike. So a hop that perfectly replaces your bittering charge might be a poor stand-in for an aromatic addition, and the honest way to do it is to decide what the original hop was actually doing in the recipe. If it was a first-minute charge, its job was bitterness and the variety barely mattered, so substituting any comparable high-alpha hop is fine. If it was a late addition or a dry hop, its job was aroma, the alpha acid is close to irrelevant, and the only question is whether the new hop smells like what you are trying to keep. Middle-of-the-boil hops sit in between, contributing some bitterness and some aroma, and those are the swaps that take the most tasting to get right, because you are trying to match two things that do not move together.
Substitute By Group, Not By Name
The most reliable substitutions happen within a family, because hops in the same aroma group are doing the same job. A noble-type hop such as Saaz, Hallertau or Tettnang, which give the spicy, herbal, slightly floral character common to continental pilsners and Bohemian lagers, can generally stand in for one another when the beer is driven by malt and the hops are a background spice rather than the feature. A modern high-alpha hop can replace any of them for bitterness, at a lower weight, but the beer will read as more modern and more resinous because that is what a high-alpha hop tastes like. American citrus and pine hops, whether of the C, A and Nugget families that were the backbone of the early craft IPA era or the newer tropical varieties, can be traded for one another when the goal is a hoppy American pale ale, though a pine-forward hop swapped for a tropical one will lean the beer toward fruit and away from resin. British-style earthy, floral and slightly minty hops cover another range, and swapping within that group keeps the earthy, herbal character that defines an English pale ale or a brown. The rule that emerges is simple, substitute inside a group for a close match, substitute across groups only when the hop is there for bitterness, and never assume two hops are interchangeable because their names sound similar, because the name describes where a hop was bred, not what it will taste like in your glass.
When To Substitute And When To Just Change The Recipe
Substitution is the right tool for three situations, which are running out of a hop you cannot get, finding a variety you like more and wanting it in a recipe, and adjusting a recipe toward a hop profile you can actually source. It is the wrong tool when you are trying to make one beer taste like a different style, because the difference between a pilsner and a West Coast pale ale is not a hop swap, it is the malt, the attenuation, the bitterness level and the water all at once, and changing the hops alone will not get you there. Substituting every hop in a recipe at once also hides the result, because if the beer changes you cannot tell which swap did it. The better habit is to change one thing at a time, so if you substitute the bittering hop and it tastes wrong you know why, and if you then change the aroma hop as well you have two unknowns and no way to learn from either. Keep a note of what you swapped and what happened, because hop substitutions are personal and subjective, and the only way to know whether your Saaz-for-Hallertau trade was an improvement is to remember making it and tasting both.
Frequently Asked Questions
Can I use a different hop at the same weight?
Only if the two hops have a similar alpha acid percentage, and if that hop is doing a bittering job. Swapping two hops at identical weight is the most common substitution mistake, because if one is a high-alpha hop and the other is a low-alpha one, using the same weight of the higher-alpha hop will make the beer noticeably more bitter, and using the same weight of the lower-alpha one will make it noticeably softer. So the weight should change in proportion to the alpha acid, and a brewer who cannot weigh to a gram scale should not attempt hop substitution by weight at all, because the error compounds. For an aroma addition the alpha acid matters far less and the same weight is often correct, since the oils are what you are after. When in doubt, match the bittering on alpha acid and match the aroma by tasting, which is why a homebrew supply shop that will weigh and bag hops to order is worth the trip when you are trying a new variety.
Do pellet and whole cone hops substitute directly?
Not quite, because the two forms behave differently in the boil, and a straight gram-for-gram swap will not give you the same beer. Pellets are usually more concentrated and more efficient, because the plant material has been milled down and the oils and resins are more readily exposed to the wort, so a pellet addition of the same variety usually gives a little more bitterness and a little more aroma than the same weight of whole cones. The gap is small enough that many recipes treat them as interchangeable and many brewers do not notice, but if you are doing a careful substitution it is worth knowing that form is another variable, along with the age of the hops and the alpha acid on the day you buy them. Whole cone hops also carry a small amount of plant material that can add a faint vegetal note to a heavy addition, which pellets do not. None of this makes pellets or whole cones wrong, it just means that when you swap, you are swapping within a set of conditions rather than in a vacuum, and the packet is telling you about the alpha acid, not about the form.
How do I know a substitution actually worked?
By tasting the two side by side and by checking the one number you can check, which is the measured bitterness, since our site notes that a bitterness reading is a laboratory figure and not the same as how bitter a beer tastes, but it will tell you if the substitution is in the right neighbourhood. Beyond the number, the real test is whether the hop character is doing what you wanted. If you substituted a bittering hop, the beer should taste about as bitter, and if you substituted an aroma hop, the beer should smell like what you were going for, and the way to know is to pour the original and the substituted beer side by side and drink them in the same sitting, ideally a day or two apart so you are not fooling yourself with the aftertaste of the last one. Most of all, trust your palate over the arithmetic, because the calculations get the bitterness into the right range but only your tongue can tell you whether the beer is better or just different, and often a substitution that measures correctly is the one that teaches you something new about your own taste.
Match The Number, Then Trust Your Tongue
Substituting hops is a two-part job, and doing the first part well is what keeps you out of trouble. The alpha acid figure lets you match the bitterness, which means scaling the weight so the high-alpha hop goes in smaller than the low-alpha hop it replaces, and that part you can get right with a gram scale and the packet. The aroma is the part the arithmetic cannot reach, because the oils that carry a hop's smell do not scale with its alpha acid, so matching bitterness says nothing about whether the new hop will smell like the old one. So the working method is to decide what each hop was doing, whether bitterness, aroma or both, match the bitterness on paper, then choose the replacement for its smell rather than its name, and taste the result next to the original. Hops from the same aroma family trade cleanly, hops from different families are safe to swap for bitterness but will change the character, and the packet tells you about the alpha acid rather than about what the beer will taste like. Get that habit in place and hop substitution stops being a gamble and becomes the most useful thing in a recipe book, because it lets you brew the beer you want out of the hops you can actually find.
