Designing a hop schedule for a hop-forward beer is more like an art project than a science project. There is science to it, but ultimately you want to add some panache, you want to shape and mold it to end up in the style and character you set out for. Whether you’re going for a big piney West Coast IPA, a tropical-fruit New England IPA, something in between, or tangential, there are ways to guide your recipe decisions.
First thing, whenever the timing of hop additions are mentioned, that reference point is set as the time left in the boil. So a 60-minute hop addition means there will be 60 minutes left in the boil when you add those hops. 0-minute hops are added just as the heat from the boil is turned off and hopstand hops are added either after a designated wait time post-boil and/or some cooling of the wort occurs. Dry hops can be added anytime after the wort is cooled to yeast-pitching temperature.
Early boil hops (45-90 min.)
The main objective of the early boil hops is to provide a firm bittering to the beer since most of the hop oils will vaporize off during the long boil. This is more important to IPAs that are looking to achieve a balance between bitter and malty sweetness that lands more on the bitter side, like in a West Coast IPA. Adding hops early in the boil has several other benefits, including preventing boilovers. The hops act to disperse the foam. A small hop addition early in the boil is recommended even when brewers look to create IPAs that are juicy or require low bitterness for balance (think brut or session IPA). Some beneficial secondary hop components will also be extracted during the long boil.
High alpha acid hops are generally preferred for this addition in order to keep vegetal matter down while still providing the alpha acids needed to achieve the desired bitterness. 1–2 oz. (28–57 g) of a higher alpha acid hop is not uncommon for 5 gal. (19 L) of a West Coast IPA, while 0.1–0.25 oz. (3–7 g) would be more commonly used for IPA styles like brut, session, or hazy.
Mid-boil hops (15–45 min.)
Back in the days prior to hopstands these hop additions, especially in the 15–30 min. range, would have been called flavor hops. As the name indicates, the goal for these hops would have been contributing less volatile hop oils as well as some more bittering components. These hop additions have lost favor in most modern IPA recipes as they can still add quite a bit of bitterness. But if that is okay in the style you are brewing, there is definitely positive hop character the mid-boil hops can add to an IPA.
A technique known as hop bursting replaces any early boil hops with a larger dose of hops added for bitterness and flavor in the 20–30 min. range. But this addition is highly optional and will be driven by your style goals.
Late-boil hops (0–15 min.)
This timeframe is what folks have traditionally called the aroma hop additions. While high-alpha, lower-priced hops may be utilized in the early or mid-boil additions, now we get into using hops that are more prized for their aromatic qualities. With the rise of the post-boil hop steep (whirlpool or hopstand) phase of homebrewing, many of these late-boil hops have all been shifted to either the end of boil or even after the wort has cooled some. These additions have also grown in quantity. Seeing 4–6 oz. (113–170 g) of hops per 5 gal. (19 L) added in this stage of a recipe is not all that uncommon in modern IPAs. But I find that you don’t really need to add that much, even for big IPAs. My sweet spot is in the 2–4 oz. (57–113 g) range. If these are added during the boil, they can contribute more bitterness, so that’s something to be aware of. But no matter what, even if you just add 1 oz. (28 g) at this stage, don’t skip it. These hops are very important in developing the character in all modern IPAs.
The hopstand is now considered common practice for brewers of all levels. This technique implies that the wort is cooled to some degree before a post-boil hop addition is made. Some brewers may add half of the late-boil hops at the end of boil, wait some time, chill down to somewhere in the range of 120–175 °F (50–80 °C) and add a another hop addition.
Finally we get to the most nuanced of all the additions — the dry hops. The type of hops, the timing of the addition, and how they are added is highly impactful. Hazy IPAs will often get a first dry hop addition earlier in the fermentation cycle, and then a second one after fermentation is complete. Many other styles of IPAs will often not receive their first dry hops until after fermentation is complete. The reason for an early hop addition is due to biotransformation of hop oils by yeast, which lends to a more fruity hop character.
Brewers of non-hazy IPAs will often try to make sure yeast has dropped from suspension prior to the addition of dry hops to give it a more raw hop character. No matter what your goal, minimizing oxygen uptake is important. Just like late-boil hops, the dry hops should not be skipped in any modern IPA. Then questions you need to answer are: What hop varietals, how much of each, when do I add them, and how do I add them? There is no one right answer to that . . .