Can I really brew a lager?

The cold, hard truth behind brewing ale’s tricky first cousin, by Beer Hawk's homebrew buyer Mark James

Often hailed as a difficult style to make at home, talk of lager homebrewing abounds with fearful phrases like “off-flavours” and “nowhere to hide”. If a porter is the hardy shrub growing in your front yard come rain or shine, a lager is surely the delicate orchid in your greenhouse threatening to collapse at the first sight of unfiltered water.

But botanical metaphors aside, is lager homebrewing really so difficult? I decided the time was nigh and resolved to brew my own Czech-style Pilsner, and I can report that by paying particular attention to two things – water and fermentation temperature – anyone can brew a crisp, bottom-fermented thirst-quencher at home.

Looking at a report from your water supplier or sending a sample off for testing will give you

Can I really brew a lager?

The cold, hard truth behind brewing ale’s tricky first cousin, by Beer Hawk's homebrew buyer Mark James

Often hailed as a difficult style to make at home, talk of lager homebrewing abounds with fearful phrases like “off-flavours” and “nowhere to hide”. If a porter is the hardy shrub growing in your front yard come rain or shine, a lager is surely the delicate orchid in your greenhouse threatening to collapse at the first sight of unfiltered water.

But botanical metaphors aside, is lager homebrewing really so difficult? I decided the time was nigh and resolved to brew my own Czech-style Pilsner, and I can report that by paying particular attention to two things – water and fermentation temperature – anyone can brew a crisp, bottom-fermented thirst-quencher at home.

Looking at a report from your water supplier or sending a sample off for testing will give you an idea of your starting point. If you need to add more minerals to reach your desired profile, that’s easy enough. But what if your desired profile has fewer minerals than your tap water, as is the case with my source at home?

The answer is to replace some (or all) of your tap water with a purified water such as distilled or RO (reverse osmosis) water. RO water is inexpensive and readily available at aquarium supply shops, so I filled a couple of fermenters with 35 litres in order to use entirely RO for my brew.

On the fermentation side, lager’s crisp, clean character comes from yeast that are cool, calm and taking their time. This is best achieved by keeping your fermenter in a spare fridge, where you can manage the temperature either with the fridge’s dial or a dedicated controller. The extended period of cold-conditioning at only a few degrees above zero is the ‘lagering’ process that gives the style its name.

Some homebrewers are experimenting with shortening this lagering period – traditional methods talk of months at a time – but a consensus exists that at least some period of cold conditioning is essential for success.