Using rainwater for brewing beer

We had a family beach house on the West Coast when I was a young man. Water came from tanks that collected rainwater from the roof.

We'd turn up in the summer holidays and Dad would check the tanks for dead possums, cos you never know.

Sometimes there would be mosquito larvae swimming around so he'd splash in some chlorine to kill them. 

Then we had to boil that water...

So I share that story so you'd think to never use that kind of water when brewing beer. 

You can use rainwater for making brews and here's a guide on doing it the right way so you don't get any mosquito larvae floating around your beer

With the recent push towards sustainability and eco-friendliness, more and more brewers are looking to use alternative water sources, including rainwater.  

Let's explore that.

Rainwater is one of the purest forms of water available. 

It is naturally filtered through the atmosphere, picking up only trace amounts of minerals and pollutants (OK, explain ACID RAIN? - ED). This makes it ideal for use in beer brewing, as it doesn't contain the high levels of minerals, chlorine, and other chemicals found in tap water.

However, rainwater can also pick up pollutants from the environment, such as car exhaust fumes and chemicals from agricultural runoff.

Some places even add healthy extras to their water such as fluoride to help with teeth health. 

For this reason, it's essential to have your rainwater tested before using it in beer brewing. A water test will tell you if there are any harmful contaminants present and if the water is too hard or soft for brewing.

Or you could not care and just do it. 

Like Micheal Jordan. 

One of the most important things to consider when using rainwater for brewing is its hardness. 

Water hardness refers to the amount of dissolved minerals, such as calcium and magnesium, present in the water. 

The hardness of the water will affect the taste and quality of the beer, as well as the performance of the yeast. If the water is too hard, it can lead to a bitter taste and slow down the fermentation process. If it's too soft, the beer will have a bland flavor and the yeast may not perform as well.

To ensure that the rainwater is suitable for brewing, it's recommended to add a water-treatment product, such as gypsum or calcium chloride, to adjust the hardness. This will also help to enhance the flavor of the beer and improve yeast performance.

Rainwater can be a great option for brewing beer but it's important to take the necessary precautions and have it tested for contaminants and adjust its hardness for the best results. 

How do I collect rain water?

Such a simple question but when you think about, there should be some method to your madness: 

• Where is your water source: The first step is to choose a surface to collect the rainwater from, such as a roof, gutter, or a flat surface. The larger the surface, the more rainwater you can collect.
• Install a gutter and downspout: If you're collecting rainwater from a roof, you'll need to install a gutter system to channel the water into a storage container. A downspout can be attached to the gutter to direct the water into a container or barrel.
• Select a storage container: The storage container can be a barrel, cistern, or rainwater tank. Choose a container that is large enough to store the amount of rainwater you need, and that is made of a material that is safe for water storage, such as food-grade plastic or metal.
• Install a filtration system: Before storing the rainwater, it's important to remove any debris or contaminants that may have accumulated on the roof or gutter. A simple mesh screen or if you are super crazy rich, a more elaborate filtration system can be used to ensure the rainwater is clean and safe for use. But if you were super rich you'd simply get the Concorde jet to bring you some snow from the Swiss Alps or something...
• Connect the downspout to the storage container: The downspout can be connected to the storage container using a hose or pipe. This will allow the rainwater to flow from the roof into the container for storage.

You should regularly monitor the water level once you are set up to make sure it's fresh for when you need it and no dead possums fall in!

Do I need to worry about bacteria in the rainwater when making beer?

The beer brewing process, including boiling the wort and malt, helps to kill bacteria in the rainwater so no bloody worries there:

During the brewing process, the wort (a mixture of malted grains, water, and hops) is typically boiled for an extended period of time, typically between 60-90 minutes. This boiling step helps to sterilize the wort and kill any bacteria that may be present in the rainwater. 

The alcohol content of finished beer can range from 4-15% ABV, which is also hostile to bacteria.+

Is hardness of water related to pH levels?

Water hardness and pH levels are not directly related, although they can both impact the brewing process. 

pH refers to the acidity or alkalinity of the water. The ideal pH level for beer brewing is between 5.2 and 5.6, which is slightly acidic. If the pH of the water is too high or too low, it can impact the yeast performance and result in a subpar beer.

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