Batch size
Batch size is the first decision to make, because everything else follows from it — fermenter size, how to split a kit in a club, and how many kegs or bottles you need at the end.
Why small batch?
BrewClub is built around small batches, and deliberately so.
Less risk. If something goes wrong on your first brew — which is unlikely, but possible — you've lost a small amount of beer, not a large one. Small batches are a low-stakes way to learn.
Less sunk cost. Smaller batches need smaller, less expensive equipment — and less of it. If you decide brewing isn't for you after one or two batches, you haven't spent a lot to find out, and nothing you bought is single-use.
More variety. A standard homebrew batch is 20 litres — a lot of the same beer to get through before you can try something different. Small batches mean you can rotate more often, brew different styles, and always have something fresh.
Drink it fresh. Hoppy beers in particular — pale ales, IPAs, anything dry-hopped, which happen to be some of the most popular styles people want to brew — are best drunk young. A 5-litre batch gets drunk at its best. A 20-litre batch of the same beer may deteriorate before it's finished.
Why is 20 litres the standard?
If you spend any time in homebrew shops or forums, you'll notice almost everything is geared around 20-litre batches. There's a good reason for it.
For all-grain brewingAll-grain brewing A brewing method in which the brewer converts raw malted grain into fermentable wort entirely from scratch — mashing the grain to convert starches to sugars, sparging to rinse the grain bed, and boiling the resulting wort with hops. Gives complete control over the recipe but requires the most equipment and time. The fourth and final stage in the BrewClub brew sequence., the biggest cost is time — mashingMashing Soaking crushed malted grain in hot water at a controlled temperature to convert starches to fermentable sugars., boilingBoiling Heating wort to a rolling boil (typically 60–90 minutes) to sterilise it, drive off unwanted compounds (including DMS precursors), concentrate sugars, and isomerise hop alpha acids into bitterness. Boiling is a hot-side process — it does not occur in Brew 1, which uses a pre-boiled kit., cooling, fermenting, cleaning, and packaging takes roughly the same number of hours whether you're making 5 litres or 20. Brewing 20 litres spreads that fixed time cost over four times as much beer, which makes it an efficient use of an afternoon. It also lines up neatly with the standard 19-litre Cornelius keg used widely in homebrewing.
BrewClub doesn't work that way. Fresh wort kitsFresh Wort Kit Ready-made wort produced by a professional brewery and packaged for home fermentation. Supplied concentrated — typically at 15 litres — with the option to dilute up to 20 litres. The brewer handles everything from fermentation onwards: sanitising, pitching yeast, dry hopping, and packaging. Removes the mashing and boiling steps entirely. Currently only available in 15–20 litre minimum volumes, making small-batch brewing a challenge without splitting. (FWKsFresh Wort Kit Ready-made wort produced by a professional brewery and packaged for home fermentation. Supplied concentrated — typically at 15 litres — with the option to dilute up to 20 litres. The brewer handles everything from fermentation onwards: sanitising, pitching yeast, dry hopping, and packaging. Removes the mashing and boiling steps entirely. Currently only available in 15–20 litre minimum volumes, making small-batch brewing a challenge without splitting.) and extract kits remove most of the time overhead — brew day is 30 minutes, not an afternoon. Cleaning is also significantly easier at small scale: pots and equipment that fit in a dishwasher are a genuine advantage, and one that disappears the moment your kit gets large enough to require hand-washing everything. The trade-off that makes 20 litres worthwhile for all-grain brewingAll-grain brewing A brewing method in which the brewer converts raw malted grain into fermentable wort entirely from scratch — mashing the grain to convert starches to sugars, sparging to rinse the grain bed, and boiling the resulting wort with hops. Gives complete control over the recipe but requires the most equipment and time. The fourth and final stage in the BrewClub brew sequence. doesn't apply here, so there's no reason to brew that much unless you want to.
FWKsFresh Wort Kit Ready-made wort produced by a professional brewery and packaged for home fermentation. Supplied concentrated — typically at 15 litres — with the option to dilute up to 20 litres. The brewer handles everything from fermentation onwards: sanitising, pitching yeast, dry hopping, and packaging. Removes the mashing and boiling steps entirely. Currently only available in 15–20 litre minimum volumes, making small-batch brewing a challenge without splitting. are currently only available in 15–20 litre minimum volumes — a deliberate constraint of the commercial production process. This makes splitting a necessity for small-batch brewing, and one of the practical advantages of brewing in a club: when everyone starts from the same wortWort Liquid extracted from malted grain during mashing and boiling, before fermentation. The starting point for beer., you can directly compare the impact of different yeasts, dry hops, or fermentation temperatures across your batches. A 10-litre FWKFresh Wort Kit Ready-made wort produced by a professional brewery and packaged for home fermentation. Supplied concentrated — typically at 15 litres — with the option to dilute up to 20 litres. The brewer handles everything from fermentation onwards: sanitising, pitching yeast, dry hopping, and packaging. Removes the mashing and boiling steps entirely. Currently only available in 15–20 litre minimum volumes, making small-batch brewing a challenge without splitting. option would open small-batch brewing to solo brewers without the need to split. This is an acknowledged gap in the market. If you're a supplier or producer reading this, we'd love to hear from you — open an issue on GitHub.
Anywhere between 5 and 20 litres is fine for BrewClub. We wouldn't recommend less than 5 litres — it's hard to get a good result at very small volumes and there's not much beer at the end. 10 litres is a good middle ground: roughly two kegs or 16–18 bottles, manageable equipment, and enough to share without committing to a large fermentation vessel. 20 litres is viable but means a significantly larger fermenter, more packaging vessels, more space, and more of the same beer to get through — especially if you're brewing solo.
Everything in BrewClub is scalable if you want more volume. But starting small is the right call.
The BrewClub base unit — 4 litres packaged
The base unit in BrewClub is 4 litres of finished, packaged beer. If you're kegging, that's one 4-litre mini keg filled with the correct headspace for carbonation. If you're bottling, 4 litres is roughly 8 standard 500 ml bottles — a case's worth.
Everything scales from this. A typical BrewClub batch is one or two of these units: 4 litres (one keg or 8 bottles) or 8 litres (two kegs or 16 bottles). Larger batches are possible with a bigger fermenter — but for a first brew, one unit is plenty.
In the homebrewing community, "batch size" conventionally means the volume going into the fermenter — not what ends up in the keg or bottle. Recipe software like Brewfather and most online resources use it this way. BrewClub uses packaged volume instead, because that's the number most people actually care about: how much beer you end up with. Working backwards from there — estimating trubTrub The layer of sediment that collects at the bottom of the fermenter during and after fermentation. Composed of dead yeast cells, hop particles, and proteins precipitated during the boil (hot break) or cooling (cold break). Beers transferred off the trub are cleaner and clearer, but a small volume loss is inevitable — typically 0.5 to 1 litre per batch depending on fermenter geometry and dry hop additions. losses to arrive at your fermenter volume, and from there your pre-boilBoiling Heating wort to a rolling boil (typically 60–90 minutes) to sterilise it, drive off unwanted compounds (including DMS precursors), concentrate sugars, and isomerise hop alpha acids into bitterness. Boiling is a hot-side process — it does not occur in Brew 1, which uses a pre-boiled kit. volume — is a more practical way to plan a small-batch brew when your packaging space is fixed. Just be aware of the convention difference when reading recipesCIP — Clean-in-Place A method of cleaning the interior of pipework, vessels, and equipment without disassembly, using pumped cleaning and rinsing solutions. Standard in commercial and microbrewery settings. Requires dedicated CIP equipment and is out of scope for small-batch homebrewing. from other sources.
Choosing your batch size
For BrewClub, the practical options are:
| Batch size | Packaged into | Minimum fermenter size |
|---|---|---|
| 4 L | 1× 4 L keg, or ~8 bottles | 5.5 L |
| 8 L | 2× 4 L kegs, or ~16 bottles | 15 L |
| 10 L | 2× 4 L kegs + bottles for the rest | 15 L |
4 litres is the minimum viable batch — one keg, or eight bottles. Good for a first brew.
8–10 litres gives you two kegs: keep one, share one (or keep both!). This is the sweet spot for a solo brewer or a pair brewing together. With 10 litres you'll also have a little extra to bottle separately — useful for comparing packaging methods or sharing with people who don't have a tap.
Beyond 10 litres, a 15-litre fermenter remains the right vessel up to around 12 litres with correct headspace — but note that FWKFresh Wort Kit Ready-made wort produced by a professional brewery and packaged for home fermentation. Supplied concentrated — typically at 15 litres — with the option to dilute up to 20 litres. The brewer handles everything from fermentation onwards: sanitising, pitching yeast, dry hopping, and packaging. Removes the mashing and boiling steps entirely. Currently only available in 15–20 litre minimum volumes, making small-batch brewing a challenge without splitting. splits don't map neatly to that volume. If you want to brew a full 20-litre FWKFresh Wort Kit Ready-made wort produced by a professional brewery and packaged for home fermentation. Supplied concentrated — typically at 15 litres — with the option to dilute up to 20 litres. The brewer handles everything from fermentation onwards: sanitising, pitching yeast, dry hopping, and packaging. Removes the mashing and boiling steps entirely. Currently only available in 15–20 litre minimum volumes, making small-batch brewing a challenge without splitting. solo, you'll need a 30-litre fermenter. That's a significant jump in equipment and volume, and not what BrewClub is designed around.
Splitting a FWK in a club
A fresh wort kitFresh Wort Kit Ready-made wort produced by a professional brewery and packaged for home fermentation. Supplied concentrated — typically at 15 litres — with the option to dilute up to 20 litres. The brewer handles everything from fermentation onwards: sanitising, pitching yeast, dry hopping, and packaging. Removes the mashing and boiling steps entirely. Currently only available in 15–20 litre minimum volumes, making small-batch brewing a challenge without splitting. (FWKFresh Wort Kit Ready-made wort produced by a professional brewery and packaged for home fermentation. Supplied concentrated — typically at 15 litres — with the option to dilute up to 20 litres. The brewer handles everything from fermentation onwards: sanitising, pitching yeast, dry hopping, and packaging. Removes the mashing and boiling steps entirely. Currently only available in 15–20 litre minimum volumes, making small-batch brewing a challenge without splitting.) is typically packaged as 15 litres of concentrated wortWort Liquid extracted from malted grain during mashing and boiling, before fermentation. The starting point for beer., designed to be diluted to 20 litres before fermenting. Diluting to the target volume gives you the result the recipe was designed for — style, balance, and strength. There are exceptions to this, but for simplicity and reliability BrewClub sticks to the standard: dilute to 20 litres and split from there. That's a fixed total volume to divide between club members.
FWKFresh Wort Kit Ready-made wort produced by a professional brewery and packaged for home fermentation. Supplied concentrated — typically at 15 litres — with the option to dilute up to 20 litres. The brewer handles everything from fermentation onwards: sanitising, pitching yeast, dry hopping, and packaging. Removes the mashing and boiling steps entirely. Currently only available in 15–20 litre minimum volumes, making small-batch brewing a challenge without splitting. bags vary in design. One common format is a bag-in-box (BiB) with a self-sealing tap — the tap closes between pours and the bag collapsesPS — Polystyrene A family of transparent, rigid styrene-based plastics used in homebrewing airlocks and accessories. Three grades appear in this register: GPPS (General-Purpose Polystyrene), SAN (Styrene-Acrylonitrile copolymer), and Styrolux SBC (styrene-butadiene block copolymer). All three are visually indistinguishable. Grade is often unspecified by manufacturers — treat as GPPS if unknown, which is the most conservative assumption for ABNS and DES compatibility. around the remaining wortWort Liquid extracted from malted grain during mashing and boiling, before fermentation. The starting point for beer., limiting air exposure to the brief moment the tap is open. In this case, with good sanitation and kept cold, a split FWKFresh Wort Kit Ready-made wort produced by a professional brewery and packaged for home fermentation. Supplied concentrated — typically at 15 litres — with the option to dilute up to 20 litres. The brewer handles everything from fermentation onwards: sanitising, pitching yeast, dry hopping, and packaging. Removes the mashing and boiling steps entirely. Currently only available in 15–20 litre minimum volumes, making small-batch brewing a challenge without splitting. may keep for up to 24 hours — useful if members need to take their portion one day and brew the next. We cover sanitation in more detail on the Sanitiser page. This is not within the standard BrewClub scope, but it's worth knowing it's possible.
Retailers and kit suppliers generally advise against splitting and storing — and there are good reasons for that beyond liability. An open bag is a contamination risk that most home brewers aren't equipped to manage reliably, and a spoiled batch is a frustrating first experience. The 24-hour window described above is a contingency for experienced hands, not a recommendation for beginners.
Some kits use an open cap or wide-mouth bladder format instead, where the exposure surface on each pour is significantly larger.
Regardless of format, the risk is the same in principle: the wortWort Liquid extracted from malted grain during mashing and boiling, before fermentation. The starting point for beer. remaining in the bag is vulnerable each time it is opened. Unfermented wortWort Liquid extracted from malted grain during mashing and boiling, before fermentation. The starting point for beer. has nothing to protect it from spoilage organisms the way finished beer does, and it can deteriorate quickly at room temperature. Same-day brewing for all members is the right expectation to set — it removes the variable entirely. Check what format your specific kit uses before the session; if in doubt, your club leader can advise.
Recommended splits:
| Club size | From 15 L | Diluted to 20 L |
|---|---|---|
| 4 people | ~3.75 L each | 5 L each |
| 3 people | 5 L each | ~6.7 L each |
| 2 people | 7.5 L each | 10 L each |
| Solo | Not recommended | — |
Any club size from 2 to 4 people works well — there's no single ideal. The main practical difference is fermenter size: a 4-person split from a diluted kit gives 5 litres each, which fits the 5.5-litre fermenter. All other splits need a 15-litre fermenter. Check the batch size table above for the right fermenter size for your volume.
It's worth noting that brewing from the undiluted 15-litre concentrate is not recommended. FWKFresh Wort Kit Ready-made wort produced by a professional brewery and packaged for home fermentation. Supplied concentrated — typically at 15 litres — with the option to dilute up to 20 litres. The brewer handles everything from fermentation onwards: sanitising, pitching yeast, dry hopping, and packaging. Removes the mashing and boiling steps entirely. Currently only available in 15–20 litre minimum volumes, making small-batch brewing a challenge without splitting. recipesCIP — Clean-in-Place A method of cleaning the interior of pipework, vessels, and equipment without disassembly, using pumped cleaning and rinsing solutions. Standard in commercial and microbrewery settings. Requires dedicated CIP equipment and is out of scope for small-batch homebrewing. are formulated for the diluted volume — brewing undiluted produces a stronger, more concentrated beer than the recipe intended, and the result may be unbalanced. Stick to the target volume.
Solo — a FWKFresh Wort Kit Ready-made wort produced by a professional brewery and packaged for home fermentation. Supplied concentrated — typically at 15 litres — with the option to dilute up to 20 litres. The brewer handles everything from fermentation onwards: sanitising, pitching yeast, dry hopping, and packaging. Removes the mashing and boiling steps entirely. Currently only available in 15–20 litre minimum volumes, making small-batch brewing a challenge without splitting. is not a realistic solo option. The total volume is 20 litres, which requires either a club to split with or a 30-litre fermenter for the full batch. If you're brewing solo, an extract pouch kit is a better fit. Extract pouches are more concentrated than FWKsFresh Wort Kit Ready-made wort produced by a professional brewery and packaged for home fermentation. Supplied concentrated — typically at 15 litres — with the option to dilute up to 20 litres. The brewer handles everything from fermentation onwards: sanitising, pitching yeast, dry hopping, and packaging. Removes the mashing and boiling steps entirely. Currently only available in 15–20 litre minimum volumes, making small-batch brewing a challenge without splitting., which makes them easier to split and store — half the pouch goes into a hot, sanitised jar and keeps in the fridge for several weeks. The process is covered on the Brew Day page.
Larger clubs
For clubs of 5 or more, two kits is the cleaner solution — it gives everyone a proper batch size without yields becoming tight. One kit split five ways from 20 litres gives 4 litres each, which is possible if needed, but fermentation losses will leave you with noticeably less than a full keg. Two kits opens up more comfortable splits:
| Club size | Two kits (diluted to 40 L total) | Per person | Fermenter needed |
|---|---|---|---|
| 6 people | 3 + 3 | ~6.7 L each | 15 L |
| 7 people | 4 + 3 | ~5.7 L each | 15 L |
| 8 people | 4 + 4 | 5 L each | 5.5 L or 15 L |
Two kits also means two styles if the club wants variety — or the same kit twice if you want a larger comparison set.
Batch size and the next decisions
Once you have your batch size, the next two decisions follow directly:
- Fermenter size — covered on the Fermenter page
- Packaging — how many kegs or bottles you need is determined by your batch size; covered on the Packaging page
Confirm your batch size before moving on.