The first recorded use of hops in beer dates back to 736, but it is believed to have been used regularly from 1500 onwards. Since then, this plant has accompanied and endowed beer with many positive characteristics.
In fact, the great number of contributions that hops provide beer with may come as a surprise to some since not only do they add the classic characteristics such as bitterness, flavor, and aroma, but hops also antibacterial properties, and they add to the stabilization of the foam, etc.
Today I’ll discuss how and when hops are incorporated during the brewing process, when to do it depending on the characteristics you’re going for (bitterness, taste, and aroma), and some additional information that you might also find useful.
So, without further ado, let’s get started!
Why are Hops added at different times?
The food codes of most countries require, among other things, that beer, in order to be called beer, must contain a minimum amount of hops and malt, and they should also be somewhat “bitter”.
Why do they need to be bitter? Well, the bitterness arises from a search for balance against the sweetness provided by the fermentables that the yeast needs to produce alcohol and Co2, and bitterness was sought even before the use of hops, usually in the form of herbs.
But over time brewers realized that bitterness was not the only thing they could get from hops and discovered that, depending on when hops were added, they could infuse their beer with other characteristics, such as flavor and aroma.
At this point, from mashing to the end of maturation, hop additions have been experimented with and increased throughout the process.
So, why are hops added at different times then?
The addition in the mash, which is hardly used nowadays, is done because at a temperature of 75 degrees Celsius it is possible to extract a certain amount of aroma and flavor and to incorporate less bitterness.
On the other hand, in the boiling process, the bitterness is what is sought after, while the flavor, and above all, the aroma, play a secondary role.
Once the wort is cold (at 20 degrees), either in the whirlpool or in dry hop, more hop additions can be made which are designed to enhance flavor, to some degree, and mostly aroma.
All of these additions will be explained in more detail below.
Adding Hops during Boil
Generally, people tend to recommend adding the hops during the boil and to do so in three additions: one for bitterness (at the beginning of the boil), one for flavor (halfway through the boil), and finally, a last one for aroma (at the end of the boil).
Why does this make a difference? Well, to answer this question we first need to know what the components of hops are. For this, I leave you a table extracted from the book “Designing Great Beers” by Ray Daniels.
Composition of hops:
|Plant material (cellulose, lignin, etc.)||40|
|Proteins||15 (0.1 amino acids)|
|Lipids, wax, pectic acid, pectin||5|
|Essential Oils||0.5 – 2|
Let’s now focus on just two of the main components: Essential oils and resins (It’s worth mentioning that Resins are made up of hard and soft resins).
The soft resins are made up as follows:
- Alpha acids: (2% to 16% of the total hop weight).
- Beta acids: lupulone, colupulone, adlupulone.
- Uncharacterized soft resins.
When exposed to the boil, the alpha-acids in the resin of the hops undergo what is known as isomerization which is responsible for adding bitterness, more on this in the next section.
As we can see the alpha-acids are fundamental, that’s why it is always important that our hop supplier includes the amount of A.A. in the package, as well as the date of packaging and the oxygen pickup.
Let’s see in more detail when you should add the hops if what you’re trying to do is add bitterness, flavor, or aroma:
To Generate Bitterness
In isomerization, the alpha-acids become iso-alpha acids, and this is what generates bitterness.
There are some things to keep in mind here: First of all, I need to clarify that there is a bitterness ceiling that can be reached. This is because the wort can absorb a certain amount of iso-alpha acids and, in the rare case that you would want an excessive amount of bitterness, from a certain amount of hops onwards the bitterness contributions will be less and less.
For a good incorporation of bitterness, some key few factors are required, but most are linked to the intensity of the boil and the time.
Then there are the organic factors, such as the type of hops used (pellet or flower), and the density and pH of the wort, with the latter value linked to the type of water, of course.
If the pH is too high it will generate a bitterness that will “clash” with that of the iso-alpha acid, resulting in undesirable flavors.
The greatest amount of bitterness occurs after 60 minutes of the boil, which means that if we want to impart a stronger bitterness to our beer, we must add the hops at the beginning of the boil and leave them there for at least 60 minutes.
Most common hops to generate Bitterness
When to add hops to impart Taste
Remember essential oils? They are responsible for the hops imparting flavor and aroma to the beer.
In fact, in some markets there are concentrates of essential oils and, by using them, we can obtain the same results while greatly reducing the vegetable matter.
However, these oils are not particularly resistant to boiling temperatures and will lose their characteristics if left there for too long.
The addition of flavor can not be left for more than 40 minutes in the boil and, therefore, it should ideally be done between 35 and 20 minutes before the end of the boil.
However, remember that this addition will introduce some extra bitterness, so take it into account when balancing the recipe.
Most common hops to generate Taste
When to add hops for imparting Aroma
In the case of aroma, the process is even more delicate than when trying to add flavor as it will evaporate from the wort after just a few minutes of boiling.
It is recommended to make this addition 5 minutes after the end of the boil or in hop stand, as the isomerization decreases enormously with just a few degrees of difference: at 90ºC it is reduced by about half.
Most common hops to generate Aroma
Important: Next, we will talk about dry hopping, but if you do not have the equipment I mention, perhaps the most sensible thing for you to do is to make the addition of aroma only in hop stand and not dry hop.
What is dry hopping?
Dry hopping consists of adding hop pellets or dried hops during the fermentation or maturation period of the beer.
This technique can be done in many ways and using different devices, but its main function is to impart a powerful and fresh aroma to the drink.
Below, I will talk about what considerations you need to take into account and also when it is best to dry hop.
When to add Hops in Dry Hop?
First of all, there are two fundamental issues that need to be addressed:
- Do you have an isobaric stainless steel fermenter?
- Do you have a slurry?
Why are these two things so important? Well, I’ve talked about dissolved oxygen in several articles and have characterized it as the beer’s worst enemy, but the point here is that dry hopping without a slurry is irremediably going to make the incorporation of oxygen a certainty.
This is why you must take some factors into consideration:
In case your fermenter is made of plastic you will have a disadvantage: You will not be able to inject Co2 into it.
We know that carbon dioxide is a way of pushing oxygen, and too much oxygen will cause the hops to degrade much faster. Therefore, if you ferment in a plastic container, you must keep in mind that you will need a larger amount of hops to achieve the same results than if you had the ability to pressurize it.
Also, since it’s not stainless steel, it’s very likely that many aromas will simply be able to “escape”.
Note: For those who don’t know what a slurry is, I’m going to attach a picture. Basically, it is a device that allows us to perform a dry hop but without incorporating oxygen.
It is clear to me that this equipment is almost exclusive to actual breweries and not home brewers and that most of you reading this will never even consider using one.
Let’s go over some tips and tricks you can use to at least prevent incorporating oxygen as much as possible:
- Dry Hop during active fermentation: When fermentation is still active, it will absorb any of the oxygen that might have made its way into the fermenter while dry hopping. Many brewers recommend adding the hops when the beer still has 5 points left to attenuate.
- Purge the yeast: Purging the yeast before dry hopping can help prevent sulfide generation.
Most common hops to add in Dry Hop
- All hops mentioned for aroma
In this article, I tried to give indications on how to use hops as efficiently as possible.
To sum up, it could be said that to generate bitterness, hops should be added at the beginning of the boil, while if the aim is to introduce flavor, the addition should be done approximately 30 minutes before the end of the boil.
For aroma, hops are added in hop stand or 5 minutes before the end of the boil.
Dry hopping also generates mainly aroma, but as I said in the article on how to clarify beer, “if when we incorporate the hops, at the same time we incorporate oxygen, this oxygen is going to oxidize the hops, and those aromas are going to end up being lost.”
Therefore it is sometimes better not to dry hop and add the aroma hops in hop stand.
There are also other ways to promote bitterness indirectly. For example, in the water treatment: if we have a favorable sulfate solution, this will help in adding a better bitterness.
The best way to learn how to take advantage of hops is to use as many varieties as possible (obviously in different brews) to get to know each type. To do this I recommend starting with a “flat” beer which allows us to bring out the bitterness, flavor, and aroma in each brew.
Frequently Asked Questions
Does the dry hop affect the bitterness? Dry Hopping adds some bitterness to the beer but to a lesser extent than in the boil. A few years ago it was thought that this was not the case because the amounts of hops used in dry hop additions were very low compared to today.
Does dry hopping affect the taste? Generally, dry hopping does affect the beer flavor somewhat, but if we have made a flavor addition during the boil, the very faint notes it can contribute are going to be very low.
Does dry hopping affect the haziness of the beer? The addition of hops when the beer is already in the fermenter will slightly add to the haziness which may not be as easy to deal with.
Can dry hopping cause oxidation? The dry hopping process can cause oxidation in the beer, and if we do not calculate the oxygen pickup, we run the risk of having done it in vain or even worsen the beer since the oxidation will take away the hop aromas causing us to waste time and money.