Despite all the modern advancements in brewing technology, such as automated brewing systems and advanced fermentation controls, the basic science behind making beer remains the same. And understanding this science is essential for brewing good beer.
Using the right brewing chemicals at the correct stages ensures clean, flavorful and stable beer. They’re used for everything from water treatment and sanitation to adjusting pH levels and improving clarity and flavour.
Here’s a breakdown of the main types of brewing chemicals used in beer making.
Contents
Sanitation Chemicals 
Just cleaning your brewing equipment isn’t enough, you also need to sanitise it. Sanitising means using chemicals to kill off almost all the tiny microbes (like bacteria and wild yeast) that could spoil your beer during fermentation or affect its shelf life. Here are a few common options used by homebrewers:
Bleach (Sodium Hypochlorite)
Bleach is affordable and works well as a sanitiser, but it has a few drawbacks. You must rinse it off thoroughly, or it can leave behind unwanted smells and flavours. It can also damage plastic and even stainless steel if it sits for too long. Plus, it takes about 15 minutes to sanitise, which is slower than other options. Many homebrewers avoid bleach for these reasons.
Iodophor (Iodine-based)
Iodophor is an iodine sanitiser that works quickly and doesn’t require rinsing. It’s popular in both brewing and medical settings. But it also has a downside. Over time, it can stain plastic equipment a brownish colour. Still, that doesn’t affect how well it works.
Starsan / Saniclean
These are no-rinse sanitisers made specifically for brewing (probably the best option to use). They work fast and can even be sprayed onto surfaces. They become inactive once beer or wort is added, so they’re safe to use without rinsing. Starsan does create a lot of foam (which is harmless), while Saniclean is a low-foam alternative if you find the bubbles annoying.
Water Treatment Chemicals
Water is the main ingredient in beer, and its mineral content can affect the final taste of the beer. So, before you start brewing, you need to find out the profile of your local water. You can do this with the help of a water test kit, which will give you readings for minerals like calcium, magnesium, sodium, sulfates, chlorides and bicarbonates.
Which adjustments to make to the water will depend on the type of beer you’re brewing. For example, IPAs prefer higher sulfates to enhance hop bitterness, while stouts benefit from higher bicarbonate levels to balance acidity from roasted malts.
Adjusting the Minerals
Once you know your water’s profile, you can add brewing salts to adjust the minerals.
- Gypsum (calcium sulfate): Sharpens hop flavours.
- Calcium chloride: Enhances malt smoothness.
- Epsom salt (magnesium sulfate): Adds magnesium and sulfate.
- Baking soda or chalk: Raises pH for darker beers with more acidic malts.
You can use online calculators to help you measure the right amounts based on your batch size.
Adjusting the pH
For best results, your mash pH should be between 5.2 and 5.6. If it’s too high or low:
Use lactic acid or phosphoric acid to lower pH.
Use baking soda or chalk to raise it.
Removing Chlorine or Chloramine
If you’re using tap water, treat it with Campden tablets to remove chlorine or chloramine. This will help prevent off-flavours in your finished beer.
Brewing Process Chemicals
In addition to hops, malt and yeast, there is also a range of chemicals that help ensure your beer turns out clear, stable and great-tasting. These chemicals are used at different stages of the brewing process to improve fermentation and enhance clarity.
Fermentation Aids
Fermentation is where yeast turns sugars into alcohol and CO₂. Certain chemicals can support healthy yeast activity:
- Yeast nutrients (like diammonium phosphate or zinc): Help yeast stay strong and active, especially in high-alcohol or nutrient-poor wort.
- Oxygenation: Adding pure oxygen or air at the start of fermentation helps yeast grow and reduces the risk of off-flavours.
Clarity Agents
No one wants a cloudy beer – unless it’s meant to be hazy. To help clear things up, fining agents can be used.
- Irish Moss or Whirlfloc (added during the boil): These help proteins coagulate and settle out.
- Gelatin, Isinglass, or Silica Gel (used after fermentation): Bind to haze-forming particles and pull them out of suspension, improving appearance.
Stabilisers and Preservatives
To prevent your beer from going stale or developing off-flavours over time, there are certain chemicals that you can use.
- Antioxidants (like ascorbic acid): Help reduce oxidation and keep beer fresh.
- Potassium sorbate (more common in ciders or sweet beers): Stops unwanted fermentation in the bottle.
- Enzymes: Some, like amyloglucosidase, break down complex sugars for better fermentation in dry styles like Brut IPA.
Common Mistakes to Avoid When Dealing With Brewing Chemicals
Chemicals for brewing can greatly improve the quality of your beer, but only when used correctly. Mistakes in handling or dosing can result in off-flavours, ruined batches, or even safety issues. Here are the most common mistakes you’ll want to avoid.
Skip Cleaning
Cleaning and sanitising are two different things. Cleaning involves removing dirt and organic material, while sanitising means killing remaining microbes. Using sanitising chemicals on dirty equipment is something you should never do.
Forgetting to Rinse When Necessary
As mentioned above, some sanitisers (like bleach) must be thoroughly rinsed after use. If you skip this step, you’ll end up with harsh chemical residues that can taint your beer. If you prefer a no-rinse option, choose chemicals like Starsan.
Not Measuring Accurately
Eyeballing chemical additions is a fast way to throw your beer off balance. Too much sanitiser can ruin flavours; too much gypsum can make your beer taste harsh. So, make sure you measure with a scale or proper measuring tool and follow recommended dosages.
Using Expired or Improperly Stored Chemicals
Chemicals tend to lose effectiveness over time, especially if exposed to heat or moisture. Always check the expiration date of the products and make sure you store them in a cool, dry place in sealed containers.
Overcomplicating It
While fine-tuning is available, using too many chemicals or trying to adjust everything at once can lead to mistakes. So, consider starting with small, essential tweaks, like sanitation or pH, and then expand as you become more experienced.
Wrapping It Up: Your Quick Guide to Brewing Chemistry
So, what’s the big takeaway from all this brewing chemistry?
Basically, making great beer isn’t just about hops, malt, and yeast – it’s also about smart chemistry. Using the right brewing chemicals at the right time is your secret weapon for making beer that’s not just good, but consistently excellent.
We’ve seen how these chemicals are vital for:
- Sanitation: This is non-negotiable! Chemicals like Starsan ensure your equipment is sterile, preventing pesky microbes from ruining your batch.
- Water Treatment: Water isn’t just water. Adjusting its mineral profile and pH with brewing salts and acids is key to shaping the beer’s flavor and ensuring efficient brewing.
- Process Aids: From yeast nutrients that keep your fermentation healthy, to fining agents that make your beer brilliantly clear, and even stabilizers that keep it fresh longer – these chemicals refine the brewing process.
The bottom line? While the science might seem a bit much at first, understanding and correctly using these chemicals empowers you to create clearer, more stable, and incredibly flavorful beer. Just remember to always clean before you sanitize, measure accurately, and store your chemicals properly to avoid common pitfalls.
Embrace the chemistry, and you’ll unlock a whole new level of control and quality in your brewing journey! Cheers to that!
