Getting cost effective at the small batch level is more difficult but with a few tricks you can reduce a lot of cost. Buying the small increments needed for small batch brewing can actually be more expensive because many homebrew shops charge a premium to sell grain by the ounce and hops are considerably more expensive in one ounce bags than by the pound or even 4-6 ounce bags. So today's post offers some ways you can trim costs. This is all mostly common sense and basic information but it's directed mostly at those small batch brewers that might be looking to step up from one gallon extract kits to all grain and designing their own recipes but not interested in scaling up to a larger batch size.
YeastThere's no great answer to how to make yeast purchases cost effective for small batches because it's not an easily divisible product. You can't buy a smack pack broken down into smaller units. You either buy it or you don't. There are some things you can do, particularly to select your yeast strains with some planning and reusing yeast. Your available storage space in your fridge will also be a concern along with your cost concerns. If you're buying liquid yeast each time you brew a small batch you are adding a huge cost to your brewing. A $6-8 vial or smack pack will almost always cost you more than the combined cost of hops and grain for a one gallon batch.
One gallon brews, along with other smaller batches, do not need a full Wyeast smack pack, White Labs vial, or sachet of dry yeast. Dumping in the full volume of yeast will definitely overpitch and there are some concerns that overpitching can lead to off flavors. You will not completely ruin a beer by overpitching so if you decide the entire volume can go in it will not be the end of the world. You do have some alternatives. With the dry yeast you can pitch a portion of the yeast and tape the sachet closed and store the rest in your fridge. The yeast will stay alive and safe to use for months that way. White Labs vials can be resealed but once opened the viability of the yeast may range from weeks to a few months, depending on the strain and how cool your fridge remains. Wyeast smack packs have no way to reseal so that is a problem if you chose to pitch a portion of the smack pack's contents.
One simple way to safely store liquid yeast is to basically treat it like washed yeast. Boil a mason jar in some water for 10-20 minutes and fill it with the water from the pot, leaving about an inch of airspace. (If you have a pressure cooker you can reach full sanitary conditions but if not you will be ok just boiling.) Once the jar cools you can pour in the remaining yeast and put the jar in your fridge. The yeast will form a compact cake at the bottom and stay viable for at least a couple months. You can make a small starter when you need to use the yeast. Make sure you label the jars.
Washing yeast is a way to stretch dollars on brewing supplies so it is something I encourage. Washed yeast will have a limited lifespan in your fridge so don't hesitate to toss out old yeast as viability will be questionable (but with enough coaxing a few viable cells can usually be found). You should only repitch yeast a few generations unless you have the ability to isolate cells because you will inevitably get some bacteria and wild yeast in your washed yeast and you'll start infecting all of your beers you're using the washed yeast to ferment. One problem you can have with washing yeast is ending up with a fridge shelf full of mason jars of yeast. There is an easy solution to the space issue in your fridge. After the yeast cake forms in the bottom of the jars when you first wash yeast, just combine the jars of the same yeast from the same batch by pouring out some of the water and adding the yeast to one or two jars. With a one gallon batch you might get 2-4 jars. You can easily reduce that down to one or two jars. That will also make it easier to reach pitching quantities for subsequent small batches.
If you are particularly ambitious about yeast you can bottle harvest from both your own homebrew and commercial beers to develop strains without having to pay for yeast quantities too big for your batch. Reaching a pitchable quantity even for a one gallon batch can take a few weeks if you're starting out with a single bottle of beer. It's only going to be cost effective if you are not buying DME to step up the colony or make starters. If you are an all grain brewer, you can sparge a little more than you need and boil those last runnings down to make starter wort. Just freeze it in some tupperware and thaw as needed. You can boil it down to a high gravity to reduce the freezer space you use and dilute for your starters.
My last piece of advice is about choosing your yeast strains. There are lots of good yeast strains available in both dry and liquid form. Homebrewers like to play with different strains -- I am no exception -- which means you either have a fridge shelf of different strains or you're buying several strains you aren't reusing. (You might bank the strains in a frozen yeast bank if you have access to a non-defrost freezer and that will avoid some of this problem.) You'll never use all the yeast you wash or could wash. If you're constantly buying new strains you're definitely not making cost conscious decisions (which is ok). However, unless you brew very different and very yeast-driven beers, you probably don't need as many strains as you use. It's fun to play with new strains and you'll need to experiment to find strains you like. What a lot of homebrewers seem to ignore is that although you can buy ten or fifteen different strains of similar flavor profile with slight differences you can manipulate one strain with oxygenation, pitching rate and temperature, to produce several flavor profiles and attenuation levels with one strain. There's no right or wrong answer with what strain or how many strains you should use. It's a balance of your cost concerns, process controls, desire to employ process controls to drive yeast behavior, and desire for particular flavor profiles.
One way to tip that balance in favor of cost control, if you are willing to wash and reuse yeast, is to brew on a schedule that allows you to reuse the yeast while it is viable. Most strains will stay safely viable in your fridge for a couple months (some hold up better than others) so if you can find a way to brew with that strain at least every couple months you can get most of a year of brewing out of one yeast purchase. If you brew a lot of beers that don't require a particular yeast profile then it's very easy to pick a neutral strain you like and reuse it frequently. However, if you are buying more expressive yeast then find some different ways to use the same strain. For example, most Belgian strains will give you fruity flavors in the 70s that work for trappist/abbey styles as well as saisons. At the lower ranges they are more phenolic so you can use that same strain to brew witbiers. English strains are more versatile than they get credit for. In the mid to upper 60s they will give you some fruity and bready notes but in the low 60s and upper 50s they will ferment out very clean so you can use the English strain for both English styles and American styles where you do not mind the slightly higher residual sweetness that English strains tend to leave behind that more attenuative American strains won't.
HopsThe easiest way to control costs for hops is to buy in bulk but by nature of small batch brewing you just won't use enough hops to justify buying each hop you use by the pound. It can also be problematic to brew a beer that uses several varieties that leaves you with fractions of ounces of hops when you scale it down to a small batch. Buying hops by the ounce can drive up the cost of your beer so small steps to save money can go far.
One very effective way to reduce your hop costs is to buy a pound of a clean bittering hop to use for all your bittering additions. Magnum is a reasonably cheap and well-used bittering hop because it has mild flavor but good alpha acid content. You can find recipes using all kinds of hops for bittering. Most people are designing recipes based on what they always use or what they have on hand. Very few recipes are designed with the intention of seeing the bittering hop add some character to the beer so it usually doesn't matter if you sub in something else you have on hand. If your local homebrew shop doesn't sell by the pound you can buy online at places like freshhops.com or hopsdirect.com which both have great products and prices. A pound of Magnum pellets runs around $11 so even with $12 in shipping (what it costs to ship to my zipcode) the $23 breaks down to $1.43 per ounce (at sixteen ounces, but hopsdirect bags are always a generous pound). That's cheaper than the $2-4 per ounce local stores charge around here. It's also very space conscious. Hop pellets survive well in the freezer and a pound takes up about the same space as a couple frozen meals. You can store them in a freezer bag and they will stay fresh for over a year that way.
There's no great way around the cost of the flavor and aroma hops when you're buying in small quantities. You can shop around for prices and try to buy in larger quantities when it makes sense. A lot of shops are now selling in four and six ounce quantities at lower costs than the per-ounce prices. You can store those extra ounces or fractions of ounces left over in ziploc bags in your freezer with minimal space requirements. As above, they will stay fresh for over a year so it's not like you have to immediately use or lose them. If you can pick some recipes to brew in a row that use some of the same hops you can buy those four or six ounce packs and save a little cash.
GrainsThe keys to controlling costs of grain really comes down to shopping around prices and planning ahead. Very few stores give price breaks on grain less than buying a full 50-60 pound bag so price comparisons on pounds and ounces matter. When you price grain online, always make sure you factor in the shipping costs compared to the grain prices locally. Some stores gouge on shipping and some local stores tend to gouge on grains, especially specialty grains. Always check to see if the price by the ounce is more expensive than 1/16 of the pound price. Some stores will only break down certain grains by the ounce so you may not always have the option to buy in an increment less than a half pound or full pound.
Give some thought to your ability to store some grain at home if you cannot find reasonable prices by the ounce. If you can dedicate a little space to some small bags of grain you can avoid a lot of the premium for buying by the ounce. Grain stores well at room temperature in ziploc bags and will stay fresh for over a year as long as it is kept free from pests (both bugs and rodents) and free from humidity that will stale grains. Unless you use every specialty malt out there your supply of specialty malt will stay fairly small and could probably stay in a shoe box in a closet or kitchen cabinet.
Planning out your beers will help here as well. If you plan several beers you can brew within a time period to use some of the same specialty grains or base grains will let you buy larger quantities at once without ending up with too much grain sitting at home. Most specialty grains are versatile enough that they can be used in enough different beers that you can brew diversely but efficiently. Roasted barley, for example, can drive a stout but also get used in a red ale, amber, biere de garde, porter, black IPA, etc. Crystal 40 or 60 can go into a wide variety of beers because it has a fairly general caramel sweetness. Again you will want to balance your desire for space and cost efficiency against brewing a beer with the flavor you desire. US crystal 60 may not cut it for you in an English beer when English crystal 55 adds just the right flavor you're after.