Making 1 gallon brews

[selectgary]

Is it a simple matter of calculation by 5th for a 5 gallons to a 1 gallon. Ingredients/water etc. wise.

 

[McKnuckle]

First of all, use the Brewer's Friend "scale" feature to turn a 5 gallon recipe into 1 gallon.

But to answer the question: Almost, but not quite. The grain bill should translate using simple fraction math. But the hops will have less utilization (lower IBU) in a small volume, even if both are perfect fractions of an original recipe (i.e. 1 oz hops in 6 gallons vs. 0.33 oz hops in 2 gallons). And there are certain water components that are more or less constant, such as your boil off rate. If you boil off 1 gallon/hr you'll do that whether you start with 6 gallons or 2 gallons (assuming the same kettle).

Try out the scaling feature and you'll see how it works.

 

[Nosybear]

Another thing you face is measurement error. The error in measuring small quantities, say 0.2 ounces of hops, is much larger than the error in measuring an ounce. If your scale is accurate to 0.1 ounces (+/-0.05 Oz), your error could be a quarter of the hops in the small batch while only a twentieth of the one-ounce hop charge. Small errors impact small batches much more than large ones so be aware of that. You also have different boil volumes but if you're doing a full boil, I don't think hop utilization changes - boil volume is not a variable used in representing utilization. I like doing 1 gallon batches to test out new recipe concepts - you only have ten bottles of bad beer if something goes wrong. But be aware of the constraints.

 

[UgliestLemming]

I switch to the metric system for smaller batches - grams and liters are more conducive to the smaller process IMO - plus 1 g of water = 1 ml of water, which is nice for water volume accuracy for mash and sparge.

 

[Ozarks Mountain Brewery]

I use grams for all my hops, its more accurate, also ounces for grain or dme, its much easier to measure

 

[Nosybear]

Just a minor engineering point: Measurement accuracy doesn't rely on units of measure but on the accuracy of the measurement device. I use a scale accurate to 0.1 g for measuring my hops but I can switch it to ounces and have the same measurement accuracy, the units are different. Think about it this way: If my scale is accurate to 0.1g, it's also accurate to .0001 kg. As long as the unit has four decimal places in its readout, the accuracy is the same.

 

[Ozarks Mountain Brewery]

you change your recipe to grams then measure with grams, instead of ounces so if it was 3/4 ounce its now 21.2 grams

 

[rouest]

Disclaimer, you didn't really ask about this, however:

As someone who does a lot of small batches, I would highly recommend doing 1.25 gallons. 1.25 is nice because at the end you will actually end up with a gallon of beer. The first few I did 1 gallon and did primary and secondary in glass jugs. I had zero headspace in primary which means a blowoff tube and lost beer and then way too much headspace in secondary due to trub/yeast cake loss. Now I do primary in a 2 gallon bucket for a week, then secondary in glass. My 2 gallon bucket also has a spigot so it doubles as a bottling bucket for my small batches.

Have fun.