Thank you for purchasing a recipe kit from The Malt Miller!

Great beer begins with high quality ingredients and carefully crafted recipes, but your passion and effort as a brewer makes a huge difference. Our team has decades of home brewing experience to share, so whether you’re a first-timer or a veteran brewer, we’ve put together this guide to help you get the most from your kit and make the best home brew you can.

What’s in this guide:

Day by day, step by step

Detailed instructions going through every step of your brew.

• Equipment you’ll need
• Water calculations and treatment
• Brewday guide
• Fermentation
• Secondary additions
• Packaging
• Conditioning
• Assessing your beer

Pro home brewer tips

FAQs and tips from our in house team covering the most common questions about your brew.

• Mashing and sparging
• Fermentation
• Your finished beer

Let’s get started!

Before you brew: equipment you’ll need

To make your kit, you will need:

• A well-ventilated, clean brewing space
• Brewing system of your choice (e.g. Grainfather, Brewzilla, mash tun and boil kettle, etc.)
• Fermenter
• Plastic or stainless steel mash paddle
• Hydrometer
• Cleaner and sanitiser solutions
• Bottles or kegs and associated bottling / kegging equipment

Before you begin, check the water calculations section below to make sure that your equipment has the right capacity for the kit you have purchased.

Optional equipment that can make your life easier:

• Countdown timer (e.g. phone app, kitchen timer etc.)
• Plastic or stainless steel spoon for stirring wort
• Plastic trug and/or buckets (great for used equipment!)
• Spray bottle for sanitiser solution
• A decent playlist of tunes to keep you focused and happy!

Before you brew: water calculations and treatment

The amount of brewing water you need depends on things like the size of your mash and the losses in your particular set-up. Losses can include evaporation in the boil, any losses to dead space, etc.

If you are using a brewing system such as the Grainfather or Brewzilla, these come with apps to calculate how much water you need for mashing and sparging. For the Grainfather G30, we’ve given the water volumes you will need on the recipe sheet included with your kit.

For other brewing set-ups, we have an easy guide to working out how much water you need here.

Treating your brewing water to remove impurities and improve flavour is simpler than it can seem. You can use bottled water, reverse osmosis water with minerals added, or tap water.

The kind of treatment needed varies depending on the water you use. As a minimum, if you are using tap water we strongly recommend using sodium metabisulphite to reduce chlorine in your beer.

You can learn more about brewing water treatment with our BREW WITH US ESSENTIALS series.

Brew day schedule

Getting ready

The very first thing you need to do is make sure all your equipment is set up and your brewing water is collected (and treated as needed). You did this the day before your brew, right? Excellent…

Next, heat your brewing water to the right temperature for adding the grain (the strike temperature). This will usually be 1-2°C above the first mash temperature listed on your recipe to compensate for any dips from transferring water around or adding grain. The exact difference will vary between brewing systems, so make a note of what you do this time and adjust next time if you need to.

Once your brewing water is at the strike temperature, grab the malt and your mash paddle – it’s time to mash…

Beginning your mash

The first part of the brewing process proper is mashing: getting sugar out of the grain and into your brewing water. If you’ve heated your brewing water all together, add the portion of mash water only to your mash tun or brewing system. Then you can add the grain. This is called doughing in.

Add the grain around a kilo at a time, stirring with your paddle to make sure it doesn’t clump up. If you have a friend to help you, have them continually stir the mash as you add the grain.

Once all the grain is added, give the mash another good stir to make sure it’s distributed evenly – then leave it alone. The mash will form a stable grain bed that will help you later on. Disturbing the grain bed can cause difficulties with sparging or even block pipes and filters.

Some brewing systems can recirculate the mash water over the grain to maintain a steady temperature. If your system has this feature, start it now, after you’ve finished stirring. Be careful to recirculate gently so you don’t disturb the grain bed. If your system has a lid, put this on to help maintain your mash temperature.

Set yourself a timer for the length of the first mash step and leave the mash to it! Grainfathers and similar brewing systems include automatic timers in their apps.

Mash steps and mash out

Some recipes include multiple steps of mashing at increasing temperatures. A very common final step is a mash out at between 75-78°C. This loosens the sugars around the grain for easier sparging.

When you have completed the time stated for each step, begin increasing the mash temperature to the next step. Once it reaches the target temperature, start another timer. Don’t count the time it takes to increase temperature between steps.

If your brewing system lets you directly add heat to your mash, you can just set the temperature on your system to the new target. If you don’t have this option, you can add hot water from your sparge water. The hotter your water is, the less you need to add to reach the target temperature. If you use this method, heat your sparge water as hot as possible, then let it cool as necessary for the sparge itself.

Sparging

Once you’ve completed the last mash step, drain the mash before beginning to sparge. Sparging is the process of rinsing off your mash grains with hot water to make sure all the sugars you’ve released go into your brew. This mixture of sugars and water from your mash and sparge is called wort.

If you have a brewing system like a Grainfather or Brewzilla, you drain the mash by lifting the grain basket into the upper position and letting the wort drip into the chamber below. If you have a separate mash tun and boil kettle, connect up the two vessels as needed and open the tap on your mash tun to drain the wort into the kettle.

Let the mash sit for a few minutes until it has drained well. Meanwhile, make sure your sparge water is at the right temperature: we recommend between 75-80°C.

To sparge, gently distribute the sparge water evenly across your grain. Keep the liquid level a few centimetres above the top of the grain bed. If the liquid level starts building up, pause and let the mash drain, then begin sparging again.

Once you have added all of your sparge water, give the mash a few more minutes to fully drain out. Next you’re onto the boil!

Boiling

In brewing systems such as the Grainfather, the heating element will kick in as soon as you complete the final mash step. This brings the wort up to boil while you are sparging to save time overall. You can pause this feature if sparging takes longer than expected.

For other brewing systems, turn on the heat to your boil kettle once you finish sparging.

While you are waiting for the wort to boil, check your recipe to see the total boil time and when to add the hops and any other included additives. We recommend you measure these out now, ahead of time.

If you have hops listed as first wort hop, add these now, while the wort is heating up.

The timings on our recipes are shown as a countdown from the total boil time: for example, “5 mins” means with 5 minutes remaining of the total time.

When adding hops, simply drop the pellets into the boiling wort. You don’t need to stir: the natural motion of the boil will distribute them evenly. This is the same for any powder or liquid additives included.

When your wort gets close to boiling, it will rise up the sides of your boil kettle or brewing system – sometimes quite rapidly! This is normal and called a hot break. If it looks like it might boil over, gently reduce the heat to get it under control. Some brewing systems adjust the heat automatically to control the boil. The hot break will pass fairly quickly, with the foam dropping away and the surface of the wort becoming visible again.

When you reach a steady, rolling boil, with small waves of wort constantly “rolling” over each other, begin your boil timer. If you have a hop addition listed for the same time as the total boil time – e.g. if your total boil time is 60 mins and your recipe lists an addition at 60 mins – add it now.

Whirlpool and chill

When you have completed the total boil time, turn off the heat. The next step is to cool the wort down to a good temperature for the yeast, but you may have some extra hops to add before then.

• For additions listed at “0 mins”, add these as soon as you turn off the heat. If there are no other additions, immediately begin to cool the wort.
• For additions listed as flameout, wait for the wort to cool to 85°C before adding. If there are no other additions, immediately begin to cool the wort.
• For whirlpool additions, let the wort cool to the temperature listed. Make your additions then wait for the time listed before beginning to cool the wort.

The whirlpool is a technique used to gather bits of hops and other solids (called trub) together in the middle of your brewing vessel. This helps you leave most of the trub behind and transfer clearer wort to your fermenter.

To whirlpool, give the wort a strong stir after adding your last hops, enough to create a current. Then leave the wort for the time listed on your recipe. You don’t need to stir again. If there is no whirlpool time given, leave the wort for around five minutes, until the current has died down.

If you are using an immersion-style wort chiller, make sure this is clean, then insert it directly into the kettle at the end of the boil. If you are using a counterflow or plate-style chiller, begin to run hot wort through it while the wort is above 85°C. The high heat will quickly sanitise your chiller.

Most wort chillers work using cold water as a heat exchanger – the colder the water, the faster you will cool the wort. If you don’t have a wort chiller and your kettle is small enough, you can immerse the kettle in a bath of iced water. You could also choose to use a no-chill cube.

The temperature you need to cool the wort down to is called the pitching temperature. The pitching temperature for your kit is shown on the recipe sheet.

Into the fermenter

When your wort is at pitching temperature, transfer it to a sanitised fermenter.

To fully sanitise your fermenter, we suggest part-filling it with sanitiser solution and shaking this around to cover all the surfaces. Then drain the solution out through all the valves and taps on your fermenter. A spray bottle filled with sanitiser solution can be useful for other equipment or to touch up any parts you handle after sanitising. Don’t forget to sanitise any hoses or other equipment used to transfer the wort, as well as the outside of your packet of yeast.

Before you pitch your yeast, take a sample from the cooled wort so you can measure the gravity with a hydrometer. The reading from this sample is your original gravity. The expected original gravity for your kit is shown on your recipe.

You can learn how to use a hydrometer with our video guide.

Make a note of the original gravity reading for reference later. The lid of your recipe box has a push-out notepad especially for this!

With the wort in your sanitised fermenter and at the correct pitching temperature, it’s time to add the yeast. The yeast should be at a similar or higher temperature to the wort. It’s a good idea to take the yeast out of your fridge at the beginning of the brew day so it can warm up.

Sprinkle the dried yeast directly onto the surface of the wort. Stir the wort with a sanitised plastic or stainless steel spoon to add oxygen. This will help the yeast to grow – just be careful not to splash or overflow the fermenter.

Lastly, cover or close your fermenter, fit an airlock, and connect up any temperature control systems you might have.

Clean up

We’re believers in cleaning up as we go along, but there will always be some cleaning to do after the wort is safely in your fermenter. Don’t be tempted to leave it for another day – it’s much easier to do immediately and reduces the chance of any nastiness growing in your equipment.

Most brew day equipment will clean up with plain hot water and a little elbow grease. Used hop “sludge” can go into compost or bagged into household waste.

For tougher or boiled-on mess, you can use a sodium percarbonate or enzymatic cleaner. These usually require a short soak then a rinse with hot water. This type of cleaner is very useful for cleaning inside counterflow and plate-style wort chillers. Pump the cleaning solution through these just as you would pump hot wort – this way you will clean your pump too.

After the brew day: Fermentation

Fermentation can be quick (just a few days) or slow (several weeks) depending on the type of yeast you’re using. You can usually observe the early stages of fermentation by seeing bubbles through your airlock. However, this is only an indicator and doesn’t tell the whole story.

The best and most accurate way to measure fermentation is to take regular gravity readings with a hydrometer. We generally take a reading every few days towards the expected end of fermentation.

Your recipe sheet includes a “fermentation profile” to follow, showing what temperature(s) to aim for at various points. If you have a temperature control system for your fermenter, set the target temperature values as needed. If you don’t have temperature control, you might choose to move the fermenter to a cooler or warmer place, depending on how easy this is. You could also simply maintain a stable temperature and add a few extra days fermentation time.

Diacetyl rests

Diacetyl is a compound produced by yeast during fermentation. It has a buttery sweet flavour that is not appropriate for most beer styles. The flavour of diacetyl is one of the most common faults in home brewed beer.

Diacetyl dissipates naturally over time. This happens more quickly at higher temperatures (above 20°C), so fermentation profiles will often include a rise in temperature towards the end of fermentation to encourage any diacetyl to break down. This is called a diacetyl rest.

You can perform a forced diacetyl test to confirm you have completely broken down any diacetyl in your beer. See our video guide to this test here.

Final gravity

When you get the same gravity reading for several days in a row, you can be confident you have reached a stable final gravity. The expected final gravity for your kit is listed on the recipe sheet.

Record the final gravity number in your notes (we’ve included a push-out notepad in the lid of your recipe box).

Once you have reached final gravity, we suggest leaving your beer for an extra 2-3 days. The yeast is still working in this period, cleaning up byproducts from fermentation and helping flavours settle down.

If you have a conical fermenter or other type with a bottom “dump” valve, at this point you can draw off sediment and spent yeast. Set up a collection vessel and carefully open the valve. You will get a first layer of sediment (trub), then creamy spent yeast, then more trub. Close the valve as soon as you see clear beer.

After the brew day: Secondary additions

Your recipe kit may include additions to make during or after fermentation, such as extra hops (dry hops), additives to make your beer clearer (finings), or other additives to improve the final flavour of your beer.

Most secondary additions should be made after you reach final gravity. Unless different timings are specified, put all the additions in at the same time to avoid opening your fermenter more than you need to.

Be sure to follow any notes given alongside the secondary additions for the best results. These notes might include setting new temperatures for the fermenter as well as the right length of time to leave the additions in.

When the secondary additions have been added and left for the time stated, the next stage is to transfer your beer into kegs, bottles, or cans, ready for drinking!

After the brew day: Packaging

If you have temperature control for your fermenter, it’s a good idea to cool your beer as much as possible before you transfer it out. A rapid drop in temperature for a few days (a cold crash) helps suspended yeast and other sediment, including dry hops, fall to the bottom of the fermenter. If your fermenter is small enough (and your fridge is big enough) you can put the whole thing into the fridge to chill.

The equipment and process for packaging your beer into kegs, bottles, or cans will vary based on your fermenter and your choice of packaging. Make sure that everything that comes into contact with the finished beer is clean and thoroughly sanitised before use, including:

• Fermenter taps and valves – spray sanitiser inside valves with a spray bottle
• Any transfer pipes and/or beer line – fully immerse these in sanitiser solution to make sure they are covered inside as well as out
• Inside and out of any siphons or other equipment for transferring beer out of your fermenter
• If using kegs, all surfaces inside your keg, plus lid, posts, and disconnects
• If bottling, bottles and caps plus inside and out of any bottle filling equipment
• If canning, cans and can lids plus inside and out of any can filling equipment

If you have a choice of packaging, some beers will suit serving from kegs and others may be better bottled.

Our recommended serving style for each recipe kit, including a target carbonation level, is included on your recipe sheet.

If you are using kegs, we generally recommend carbonating by pushing CO2 from a gas cylinder into the beer (force carbonation). See our complete guide to kegging and force carbonation here. The lid of your recipe box includes a push-out keg hanger so you can note down what’s in your keg, as well as the date you packaged it.

If you are using bottles, we recommend adding priming sugar to each individual bottle before filling. This ensures a consistent level of carbonation in each bottle. You can use dextrose, table sugar, or carbonation drops.

If you are using cans, we recommend force carbonating in a keg and using a counter pressure can filler.

After packaging: Conditioning

As tempting as it might be to guzzle all that delicious beer as soon as it’s packaged, some beers will benefit from some conditioning time so you can enjoy them at their best.

• Beers that have been force carbonated should be allowed 24 hours after packaging to settle.
• Beers that have been carbonated using priming sugar or carbonation drops should be allowed around the same amount of time as primary fermentation (the time between original gravity and final gravity of the main beer).

After the initial settling period, the conditioning time will vary by the style of beer.

• Very hoppy beers should be kept cold and enjoyed as soon as possible.
• British and malt-forward ales will benefit from 4-6 weeks conditioning time.
• Lagers benefit from 1-3 months conditioning as cold as possible.
• Dark and higher alcohol beers tend to keep improving with age.

After packaging: Assessing your beer

One of the most fun parts of home brewing is enjoying your final beer with friends or family. You might also choose to share your creation with a home brew club or enter into a competition.

Your recipe sheet will include some notes on how this beer should look and taste so you can assess your version against ours!

Mashing and sparging

What if I don’t have temperature control on my mash tun – what do I do about mashing out?

If you don’t have the option to directly add heat to your mash tun, you can add hot water from your sparge water. The hotter your water is, the less you need to add to reach the target temperature. Heat your sparge water as hot as possible, then let it cool as necessary for the sparge itself.

What if I don’t hit my expected mash pH?

First, remember that you should wait until around 15 minutes into your mash to take a pH reading to make sure you have an even, accurate reading – before this point the pH may not be stable across the mash. It can also be a good idea to allow your sample to cool to room temperature before you test it, especially if you’re using pH test strips or a digital meter that doesn’t compensate for temperature.

The ideal pH range for your mash is between 5.2 and 5.6. This gives the best conditions for the enzymes in the mash to work. However, the enzymes do still work outside this range, just a little less efficiently. Hitting your expected pH sets you up with the best chance of an efficient mash, but being a little out won’t do any harm.

Making adjustments on the fly can be complicated, so just make a note of what measurement you got this time vs what you expected. Then use this to adjust your brewing software so you get a more accurate prediction next time. It can take several brews to work out the correct adjustments to use.

What if my mash recirculation gets stuck or blocked?

A strong mash recirculation sounds like a good idea on paper, but this can have the same effect as stirring your mash after initial doughing in. All those little grain particles can become separated from the grain bed, then get into the gubbins of your pump and ultimately block it.

If this happens, stop recirculating immediately and drain your pump. If you can get the pump to restart, go more slowly to help gently ease any remaining blockage and re-set the grain bed. You might try adding a little more water to thin out the mash a bit – take this from your sparge water.

If the pump won’t restart at all, leave it off and don’t recirculate for the rest of the mash.

What if I have a slow sparge or transfer – or it gets stuck altogether?

A slow (or even stuck) sparge can mean that your grain bed has gummed up. Our recipe kits are carefully crushed with extra grain husks added as necessary to form natural channels in your grain bed and help avoid this problem, but a stuck sparge can sometimes still happen.

It’s important when sparging to be patient and keep the liquid volume a few centimetres above the grain bed. Too much sparge water at once can overwhelm the natural channels, so go slowly. By the same token, don’t let the sparge volume fall below the top of the grain bed until the very end. You want a steady flow throughout rather than one that stops and starts. This is a common cause of a stuck sparge.

If things do get stuck, you can try increasing your sparge temperature to loosen the grain bed, though keep it below 80°C. If the overall temperature of the grain bed goes above 80°C you may start to extract some harsh flavours.

You can also try raking small channels across the top of the mash with your mash paddle. The idea here is to help the sparge water find natural paths through the grain, while disturbing the grain bed as little as possible. Don’t rake too deeply as this could disturb the grain bed.

As a last resort, you might have to stir the mash to get the liquid flowing – just be aware that this will probably release a lot of fine grain particles into your wort, which could block pumps and valves later on. So stir the least amount possible to get things moving.

What if I don’t hit my target original gravity?

If you’re measuring your gravity after your mash with a refractometer, you have the option at this point to either boil for a little longer to produce a stronger wort (if your gravity is lower than you expected), or to add more water to dilute wort to the target (if your gravity was higher than you expected). You can also add dried or liquid malt extract to bump up gravity.

Or… you can choose to leave your brew as is. Some of the fun of home brewing is in the variation, and being one or two points out is part of what makes this brew yours, not ours. All of our team has had brews that come out stronger or weaker than expected, and the vast majority of the time that’s fine!

If you’re measuring your gravity after your boil, we definitely say take this as is and chalk it up as part of the experience.

I put this recipe into my brewing software and it came out with different numbers!

The numbers in a brewing recipe are estimates only. For gravity numbers, these are like target numbers to help you know if you’re in the right area. For colour values or IBUs (a measure of bitterness), these are indicators to give you an idea of what sort of beer you’re making – the only way to get an actual IBU value from your beer is with lab testing!

All these numbers are based on calculations and assumptions. Each brewing software package uses a slightly different set of calculations and assumptions: for example, how much you sugar you might extract from a particular malt or how much bitterness a hop gives. There are so many variables involved it would almost be more surprising if you did manage to get a match for all the numbers in a recipe!

In short, numbers from software don’t matter that much. What does matters is the actual results of your brew! Take lots of notes as you go along. You can then use these to dial in your software and equipment so you get more accurate estimates in future.

Fermentation

Why hasn’t fermentation started yet?

The time between adding your yeast and the first visible signs of fermentation is called lag time. Lag times depend strongly on the type of beer you’re making, how your mash went, and what type of yeast you’re using. Any time between 12-72 hours is normal.

What if I don’t have temperature control on my fermenter?

If you don’t have a temperature control system for your fermenter, you might choose to move the fermenter to a cooler or warmer place, depending on how easy this is. You could also simply maintain a stable temperature and add a few extra days fermentation time.

When it comes to cold crashing, if your fermenter is small enough (and your fridge is big enough) you can put the whole thing into the fridge to chill.

How long does fermentation normally take?

This depends on the type of beer you’re making and the exact strain of yeast you’re using. Your recipe will give you an indication of how long is normal for this particular kit. However, it’s not unusual for some fermentations to last days or even weeks longer or shorter than expected: for example, if the actual fermentation temperature is a lot different than suggested.

Patience is almost always the answer!

How do I measure progress of my fermentation?

You can usually observe the early stages of fermentation by seeing bubbles through your airlock. However, this is only an indicator and doesn’t tell the whole story. Never rely on bubble activity as the only measure of fermentation.

The best and most accurate way to measure fermentation is to take regular gravity readings with a hydrometer. We generally take a reading every few days towards the expected end of fermentation.

How do I know if fermentation has finished?

When you get the same gravity reading for several days in a row, you can be confident you have reached a stable final gravity.

Once you have reached final gravity, you should leave your beer for an extra 2-3 days before moving to the next step. The yeast is still working in this period, cleaning up byproducts from fermentation and helping things settle down.

What if fermentation stops sooner than expected?

There are lots of variables that affect how quickly fermentation will complete. If you’ve reached the expected final gravity sooner than expected, don’t worry. Remember to give the beer a good few extra days to make sure it really has finished and the yeast has cleaned up after itself.

If fermentation seems to have stopped a long way above your expected final gravity (more than 10 points, e.g. 1.030 instead of 1.015), your fermentation may have got stuck. The first thing to try here is to increase the temperature a little. Give this a few days and see if it gets the yeast going again.

If not, you can try to “rouse” the yeast by gently swirling the sealed fermenter. Don’t be tempted to open the fermenter or stir the beer. This can cause oxidation and ruin your beer.

If these steps don’t get things moving, you can try pitching some more yeast. Use the same strain as the one included with your kit to get the right flavours. If you’re going down this route it’s a good idea to put some extra yeast nutrient in alongside the yeast to give the new packet the best chance.

If nothing happens a week or so after this, and you still have the same gravity reading as before, this is probably a stable final gravity.

What if I don’t hit my target final gravity?

It’s worth bearing in mind that the expected final gravities on our recipes are estimates based on our processes and in-house home brewing equipment. Your own brewing set-up and practices are what make this your beer, not ours – so if it’s a couple of points different to ours, that’s not a problem. Just be sure it’s a true, stable final gravity before you package the beer.

Your finished beer

My keg is all foam!

If the beer you’re serving is far too foamy, this could be fobbing, caused by the beer serving line or tap you’re using.

If you still have problems, it could be that your keg is simply over-carbonated. Gently bleed off some gas pressure using the pressure release valve, then let the keg settle for a few hours. Repeat as necessary.

My bottles are exploding!

Hopefully they aren’t literally exploding – this is why we sell PET plastic bottles rather than glass!

If you have very high levels of foam then there is probably too much CO2 pressure inside the bottles. This could be from too much priming sugar or if the beer was bottled before it reached final gravity.

First, try chilling your bottles in the fridge. Cold temperatures help the CO2 to absorb into the beer. The CO2 will release when you pour but this should help stop the beer coming out as a fountain!

If you still have problems, put your chilled bottles into the sink and unscrew the caps the least amount you can manage. This will gently bleed off some CO2. Leave for half an hour, then try pouring another bottle. If it’s still too foamy, unscrew the caps a tiny amount more. Repeat as necessary.

My beer doesn’t taste as I expected?

You’ve put a lot of effort into making your beer – so it can be disappointing when it doesn’t taste like you thought it would.

The first thing is to get a second opinion to make sure you’re not being overly critical. Then re-check the tasting notes for the kit. If it doesn’t match up, think about why this might be. For example, if the timing of your hop additions was different than the recipe (brew days can be busy, this sort of thing happens!) your beer could end up more or less bitter than expected.

For truly unpleasant flavours, you might have a more serious issue.

My beer isn’t the colour I expected?

Beer colour is affected by all sorts of things, even how clean your glassware is, or the position of the main light source in your room.

Much darker than expected colours can result from overheating or scorching during the mash – you would normally be able to smell this happening at the time. You can also get darker colours from over-long boil times.

Paler than intended colours sometimes come along with lower than expected original gravity readings, indicating your mash was less-efficient than expected.

Cloudiness or haziness can also affect your perception of colour. One of the most obvious colour flaws is oxidation, which can give hazier beers a dull grey or even cardboard-brown colour.

I think my beer is oxidised?

Oxidation means your beer has been exposed to the air too much after fermentation. Just like a cut apple goes brown, the colours and flavours of your beer change quickly in the open air.

Hazy IPAs are particularly at risk of oxidation: hop flavours can go dull and, in extreme cases, your beer could turn grey or cardboard-brown. However, all beers will suffer with oxidation, with malt flavours taking on a papery, slightly vegetal note, and an overall loss of aroma and character.

Yeast needs oxygen to grow at the very start of fermentation, but after this point you should try to avoid introducing oxygen wherever you can. In general this means keeping your fermenter closed as much as possible, avoiding stirring or splashing the finished beer, and taking steps to reduce oxygen contamination when packaging your beer – for example, purging kegs with CO2 before filling them.

For beer styles that are particularly sensitive to oxygen, we recommend using kegs and forced carbonation rather than bottling. This is because bottling and carbonation with priming sugar has a naturally higher risk of oxidation. If you prefer you can still put these beers into bottles and just take extra care.

I think my beer is infected?

You generally can’t mistake an infection in your beer – the flavours are usually very obvious.

If your beer is sour and it wasn’t supposed to be, this could be a bacterial infection. Vinegar-like sourness indicates an infection with Acetobacter, which is very commonly carried by fruit flies. A more yoghurt-like sour flavour could mean infection by lactic acid bacteria such as Lactobacillus, which is naturally found on the husks of barley and wheat.

Phenolic flavours can range from medicinal to spicy. These indicate wild yeasts at work in your beer. You might also see unexpected behaviour during fermentation, such as much lower final gravity than expected.

Mould is the worst kind of infection but also usually only happens in the rarest circumstances. Moulds can contain dangerous toxins and it is hard to identify them without lab testing. To be safe, if you see any mould on your beer do not drink it. If you see any mould on your equipment you should replace that part before making any more beer.

If you believe you have an infection in your beer, do not drink it (you probably won’t want to anyway). Thoroughly clean any stainless steel equipment with a strong alkaline cleaner. Smaller items can be immersed in boiling water. We recommend replacing any plastic and/or rubber/silicone equipment you used in this batch, including any hoses or beer line. These materials can harbour infections in small scratches even after thorough cleaning and are a common cause of reoccurring infections.

To avoid infections, make sure your equipment is always stored clean and is clean before and after each use. Keep your workspace clean and tidy, away from insects or pets, and thoroughly sanitise anything that comes into contact with your beer after boiling. Boiling will kill most harmful agents but it’s obviously sensible to not be too sloppy with cleanliness before the boil!

If you keep everything clean and sanitary you are unlikely to get infections. Just be careful and you won’t have to worry!