Small Batch BIAB Experimenting
Some homebrewers love to brew a recipe until it’s perfected, making it their go-to batch. Others never brew the same thing twice. I write a lot of recipes, some of which can be found on those recipe cards in this very magazine. Although most of my equipment is best suited to brew 5 gallons (19 L) of all-grain or extract batches at a time, I like to keep equipment around for smaller batches, giving me the option to easily tweak and trial a recipe.
Experimenting with ingredients is where I find 1-gallon (3.8-L) Brew-In-A-Bag (BIAB) really handy. This goes for all five major variables — water, hops, malt, yeast, and “other,” which can include fruit, types of sugar, herbs, vegetables, oak or really, anything edible or that you’d like to use to flavor your beer.
I’ll also note that I have found small batches may not be as helpful depending on your equipment and goals. Although it is easier to control all parts of your process, small changes in small batches often equal big changes in larger batches. If you are looking to lager a beer, you may not have the means to control your step-mash temperatures, water volumes, sparge and fermentation temperatures as easily when you try to step the batch up to a larger volume batch. If you are only looking to brew your batch once, as a small batch, you’ll find some things much easier, and it’s well worth your time, as you may be able to brew a style you otherwise typically couldn’t.
The Tools of the Small Batch Trade
You may find you already have nearly everything you need for a BIAB 1-gallon (3.8-L) batch of beer. Here are the most helpful items:
Graduated 8- to 20-Quart (7.5- to 19-L) Kettle: Your current brewing kettle might be a bit big to really steep properly. I’ve found anything bigger than a 20-quart (~5 gallon) kettle often leads to a no-sparge mash in terms of mash water necessary to cover the grains. Without a giant mash bag, you need the extra water to keep your grain soaked.
Thermometer: You may not have a glass or metal thermometer for your boil if you’ve only been brewing with extract, or extract and steeping grains. To keep your mash temperature in range, and to bring your hot liquor water and sparge water to temperature, you’ll need one.
Stainless Double-Mesh Strainer: A strainer will allow you to sparge your grains a bit after your mash is complete (if you want). A strainer in the 10–12-inch (25–30- cm) range that can rest on the edge of your kettle is ideal. You can find one of these at any kitchen supply store and many homebrew shops.
Large Steeping/Mash Bag: This can be a cotton or nylon bag. I like to use a large bag so that my mash can be easily submersed in my kettle.
(Optional) 5000-mL Borosilicate Glass Erlenmeyer Flask: My weapon of choice when boiling 1-gallon
(3.8-L) recipes (extract, all-grain, BIAB or otherwise). It can be used to heat mash water, sparge water, you can boil your wort with one, and you can ferment your small batch in it. Really, the only step I wouldn’t recommend in a flask is mashing as obviously the narrow neck of the flask would impede getting grains in and out of the vessel. Please note, however, that heating an Erlenmeyer flask is only suitable for propane/gas heating elements. Electric stoves can cause the flask to break when exposed to heat. If you have an electric stove, you can simply boil in your graduated kettle. And if you don’t want to use an Erlenmeyer at all, you can of course ferment in a 1-gallon (3.8-L) carboy fitted with an airlock as many small-batch brewers do.
Recipe Design Basics
When designing a recipe you need to decide what your goal is, and starting point. If it’s to make a vanilla porter better than anything you’ve ever had, you know you’ll probably be using dark malt and vanilla in some form. If it’s to improve or adjust a recipe you’ve previously brewed, have an idea what you liked and didn’t like about the previous recipe, because once you start adding and subtracting ingredients, you’ll gain some real perspective on what caused the good and the bad. Try and only change a single ingredient at a time — you’ll learn so much more about the ingredients you use by only changing one aspect of your recipe at a time. For more about designing a homebrew recipe, check out Brad Smith’s story in the January-February 2014 issue of Brew Your Own, or his story on SMaSH brewing (single malt, single hop brewing) in the July-August 2014 issue. Small batch BIAB is a great way to try out experimental, simple recipes such as SMaSH. For example, I recently made a pale ale that was good, but a bit on the simple side in regards to the malt flavor. I was personally looking for a sessionable pale ale, using a favorite hop, Centennial. Although the beer consisted of only a single variety of hop, I enjoyed what Centennial brought to the recipe. What I found missing was an extra dimension to the malt. One option, changing the yeast, could make the malt in the original recipe more dynamic, but I also thought it could be done easily through the malt bill. I was using Briess’ Full Pint Brewers Malt, which already provided a slight bready and malty flavor. I now knew what this unique base malt would provide, and wanted to accentuate its characteristics further. I decided to base my small-batch BIAB experiments around two other interesting light roasted malts — Briess Victory® and Special Roast. I believed both would bring the bready side of the Full Pint Brewers Malt out, but which would work best in balance with the Caramel 40 °L and the Centennial in the recipe? I used my small batch BIAB setup to find out.
Let’s Brew Two
One advantage I’ve found to the small-batch BIAB technique is the ability to maintain two batches, side by side, at once. I’ll do this by staggering my start by 15 minutes for each batch so that important steps in the process aren’t coming up at the same time. If you don’t have the equipment or space to boil two batches at once and want to do a side by side comparison, brewing two batches back to back, although a bit more time consuming, works as well.
If you are tweaking a recipe, and want to keep your measurements as close as possible, most brewing software has a handy tool that allows you to scale your batch down to a gallon (3.8 L).
The Brewing Process
Although I typically use around 1.3 quarts (1.2 L) of water per pound of grain when brewing larger batches, you may find you need additional water to keep your grain soaked when doing 1-gallon (3.8-L) BIAB. Your kettle may be a bit large, or your bag a bit small. That’s ok, use the additional water, and make note by subtracting what was used from your flask total. See the photo of my flask-as-hot liquor tank above.
In the example for this story, I steeped in two recipes using two different techniques. I’ve used both but never side by side, and was trying to perfect my own process for 1 gallon (3.8 L) BIAB. One I did using a closed cotton bag in a tall kettle, another using an open nylon bag in a shallow kettle. Again, process is important but often hard to scale up.
I try to measure the temperature in the grain, often sticking my cotton bag with the thermometer creating a hole I’ll reuse to take temperature. If you find you’ve lost too much heat, which happens with stovetop brew in a bag, turn your heat on medium-low. If you don’t have a very thick-walled pot, continually stir your bag around so it doesn’t rest on the bottom in one spot too long — the bag can burn or melt to the bottom. Lift the bag up and stir water over the grain. When the target temperature is reached, close the lid. I like to check every 10 minutes or so for temperature. This process is a bit more time consuming than some homebrewing methods, and you may find you put more time into a 1-gallon (3.8-L) mash than you do for a 5-gallon (19-L) mash, which may just sit in a cooler for an hour without any babysitting. I find my open bag BIAB mashes need much more tending and stirring to maintain temperature.
Water can be poured directly from the flask over the bag to sparge, while the grain rests just above the kettle in your strainer. For today, my efficiency in my ‘closed’ BIAB mash was 3% higher at roughly 72% brewhouse efficiency, compared to only 69% for my open BIAB mash, which I tended to more often. I actually rinsed with less sparge water for my closed BIAB mash as well, since more was used during the mash itself. The grain more easily maintained temperature in the closed bag, while the grain in the open bag was cooling quickly, exposed to the air temperature.
For this experiment, I decided to do a side-by-side boil comparison as well. My Victory® malt batch (which was open bag mashed) ended up being transferred to an Erlenmeyer flask for the boil. I left my Special Roast Pale Ale in the mash kettle — a single mash/boil vessel is an advantage to BIAB, so it makes sense to use it!
The wort in the Erlenmeyer flask didn’t need a lot of heat to boil, but the disadvantage was that steam became trapped in the narrow opening, allowing volatiles (undesirable compounds) to settle back in to the boil, as well as making me extend my boil to ensure I boiled off enough to get 1 gallon (3.8 L) in the end.
The kettle had none of the boilover issues the flask had, and with such a small batch in a 5-gallon (19-L) kettle, I really didn’t have to watch for boil overs, though I did have to watch that I wasn’t boiling too vigorously — it doesn’t take much to boil a gallon.
Keep in mind that small changes, even a bad boil over, when brewing a small batch can lead to a large deviation. Having more or less of anything in the small batch is amplified by 5, when compared to brewing a typical 5-gallon (19-L) batch. Being off 2 ounces (57 g) of malt in a 1-gallon (3.8-L) batch is like being off 10 ounces (283 g) when brewing a 5-gallon batch. Boiling down to 1.25 gallons (1.18 L) instead of 1 gallon
(3.8 L), is like boiling to 6.25 gallons (6 L) instead of 5 gallons (19 L). Small quantities become critical. Measure carefully.
After adding hops at flame out (zero minutes) I immediately removed both the kettle and flask from the heat. The flask can handle dramatic changes in temperature. I ran room temperature water over it to clean up some of the boil over as well as to cool the wort down some.
I immediately put a stopper and airlock on my flask I boiled in, a nice plus to this method. Again, if you don’t have a gas stove, simply boil in your kettle and transfer the wort to a sanitized 1-gallon (3.8-L) carboy. I also gained an advantage from the high temperature tolerance of the flask when transferring my boiling wort from the kettle immediately without worry of shattering a glass carboy or having any low-grade plastics issues. I found transferring to the flask easiest dumping through a funnel. Both batches were two gravity points apart, to be expected with my mash efficiency being slightly lower on my Victory® Pale Ale.
After letting both ferment, and tasting them a week in out of the primary, I was personally surprised to notice the slight malt bill difference. Of course, both batches weren’t brewed in a vacuum, so there were also fermentation and process differences noticeable as well. With my experiment nearing its end, initial tasting notes taken, I plan to carbonate both batches and determine which will be the next 5-gallon (19-L) BIAB batch on tap at home.
Go Small At Home
So with this information, you are armed with all you need to know to set up your own BIAB pilot homebrew program. If you’re not ready to design your own recipes, or want to try brewing those that I used to write this story, check them out below.
When sparging I’ve found having a double-mesh strainer makes life easier. You can get a strainer at most kitchen supply stores, and frequenly at homebrew shops that stock equipment.
SMALL BATCH BIAB RECIPES
Special Roast Pale Ale
(1 gallon/3.8 L, all-grain)
OG = 1.055 FG = 1.014
IBU = 43 SRM = 10 ABV = 5.4%
Briess’ Special Roast malt is a Biscuit-style malt with toasty, bran flake, sourdough-like flavors, and features a deep golden to brown hue.
Ingredients
2 lbs. (0.91 kg) Full Pint pale malt
2 oz. (57 g) crystal malt (40 °L)
2 oz. (57 g) Briess Special Roast malt (40 °L)
1.3 AAU Centennial hops
(60 min.) (0.18 oz./5 g at 7.4% alpha acids)
2.1 AAU Centennial hops
(5 min.) (0.28 oz./8 g at 7.4% alpha acids)
0.35 oz. (10 g) Centennial hops (0 min.)
Safale US-05 or Lallemand BRY-97 (American West Coast Beer) yeast
0.88 oz. (25 g) corn sugar (if priming)
Step by Step
Heat 9.6 qts (9.1 L) of water up to 158 °F (70 °C). Stir the crushed grains and water in the bag so that the mash temperature stabilizes at 154 °F (68 °C) and hold for 60 minutes.
After the mash is complete, remove the bag and squeeze the grains until you have approximately 2.25 gallons (8.5 L). Boil the wort for 60 minutes, adding the hops at times indicated in the ingredients list. At the end of the boil you should have just over one gallon (3.8 L) of wort. Add the final hop addition and let stand for 15 minutes before chilling the wort.
Chill the wort down to 68 °F (20 °C), oxygenate, then transfer it to your sanitized fermenter. Hold the fermentation temperature for 4 to 5 days, then slowly increase temperature to 70 °F (21 °C) until
fermentation is complete. Prime and bottle condition, or keg and force carbonate to 2.5 volumes of CO2.
Victory® Pale Ale
(1 gallon/3.8 L, all-grain)
OG = 1.055 FG = 1.014
IBU = 43 SRM = 9 ABV = 5.4%
Briess’ Victory® malt is similar to Special Roast in that it is a Biscuit-style malt. It has toasty, nutty, clean flavors and is also deep golden to brown in color (like Special Roast).
Ingredients
2 lbs. (0.91 kg) Full Pint pale malt
2 oz. (57 g) crystal malt (40 °L)
2 oz. (57 g) Briess Victory® malt (28 °L)
1.3 AAU Centennial hops (60 min.)
(0.18 oz./5 g at 7.4% alpha acids)
2.1 AAU Centennial hops
(5 min.) (0.28 oz./8 g at 7.4% alpha acids)
0.35 oz. (10 g) Centennial hops (0 min.)
Safale US-05 or Lallemand BRY-97 (American West Coast Beer) yeast
0.88 oz. (25 g) corn sugar (if priming)
Step by Step
Heat 9.6 qts (9.1 L) of water up to 158 °F (70 °C). Stir the crushed grains and heated water in the bag so that the mash temperature stabilizes at 154 °F (68 °C) and hold for 60 minutes.
When the mash is complete, remove the bag and squeeze the grains until you have approximately 2.25 gallons (8.5 L). Boil the wort for 60 minutes, adding the hops at times indicated in the ingredients list. At the end of the boil you should have just over one gallon (3.8 L) of wort. Add the final hop addition and let stand for 15 minutes before chilling the wort.
Chill the wort down to 68 °F (20 °C), oxygenate, then transfer it to your fermenter. Hold the fermentation temperature for 4 to 5 days, then slowly increase the temperature to 70 °F (21 °C) until the fermentation is complete. Prime and bottle condition as usual, or keg and force carbonate the beer to 2.5 volumes CO2.
