Ever since I started brewing beer at home three years ago, like many serious home brewers I’ve gradually evolved from the basic malt extract kits to partial mash from a recipe (half extract, half grain) to BIAB (brew in a bag) and within the past six months to experimenting with all-grain brewing (what online beer suppliers call “advanced” brewing). I’ve done three all-grain batches so far, not nearly enough to even begin to understand how all the complicated processes work together to create a palatable beer, but so far I have brewed a Belgian Wit Bier, a Pumpkin Ale, and a dark “gingered” ale all using all-grain brewing techniques.
I discovered a few things from AG (all grain) brewing.
Moving from those pre-formulated, recipe-bound extract kits to creating recipes for all-grain brewing inevitably requires an understanding of a multitude of different sciences. I was surprised by how many different fields of science were involved. The chemistry and physics involved with the brewing process, including the science of zymology (I love that word), grain production and malting, chemical testing and measuring procedures, and the wide variety of brewing equipment and techniques available to the home brewer, can quickly overwhelm the non-science student, such as me.
Once I went to AG brewing, I quickly saw how many different variables affected the success of the final product. The use of LME (liquid malt extract), for example, ensures greater success because the characteristics of the extract are already determined, e.g. specific gravity, fermentability, wort color, and usage rate (6 lbs. extract produces 5 gals. of wort). The challenge of AG is to make your own extract that’s “good enough” to replace LME in a kit. It’s more work because of the complexities of mashing: crush of the grain, temperature of the water, target specific gravities, and so on.
With so many variables affecting the AG brewing process, I know things can go wrong fast. I don’t pretend to be a connoisseur beer. I couldn’t tell you the difference between a lager and an ale or a stout and a porter. I’ve liked the taste of all of the beers I’ve made from a recipe. If there was a problem with the taste of the beer, it would have to be pointed out to me by someone who knows more than I. That’s a problem I think I’m facing with AG brewing: knowing the style of beer I want to brew and whether or not the final product meets the style’s standards of taste. That takes a good recipe, good measuring, good equipment, good technique, patience, and a willingness to learn from mistakes. Of course, it also takes at least some understanding of the characteristics of the different styles of beer.
So my most recent batch is from a Belgium Witt Bier recipe. How close the final product matches the style of beer, its taste, color, and level of alcohol, depends on how successful I was at completing each stage of the process. The most important piece of equipment I have is the hydrometer, followed by an
accurate thermometer. Mashing efficiency, one measure of a successful batch, is determined by a target specific gravity set by the recipe. The Belgium Witt recipe set a pre-boil gravity of 1.053 and a final gravity of 1.015. I missed those targets. I had readings of 1.043 pre-boil gravity and 1.013 final gravity.
Possible causes of lower gravity readings (well-researched online). Conversion: incomplete conversion of starches to sugars can affect hydrometer readings—less sugars in the wort mean lower gravity levels and lower alcohol by volume levels; water to grain ratio: higher water ratio means less sugars and a lower gravity; grain crush: the finer the crush the greater the efficiency, meaning higher gravity readings.
Before coming up with ways to hit my pre-boil gravity, I need to make sure the thermometer and hydrometer are accurate. Water volumes are important at each stage and need to be accurate. Too much wort in the primary means water volume is too high. Easy enough to account for accurate water volume before the boil, but after boil volume is important. There is a correlation between the volume of water lost due to boil and the length and “intensity” of the boil. BTUs affect the ability to have a vigorous boil. A vigorous boil is a rolling, bubbly, just short of a boil-over kind of boil. The less intense the boil the longer the boil must be to ensure post-boil volume.
I need to be sure all the starches have converted into sugars next time, using the iodine test. I know a coarse grain crush produces less sugar by volume than does a finer crush. I have to assume that the mill at my local home brew supply gives an optimal crush at .035. Efficiency in conversion is affected by temperature, type of lauter tun (bucket-in-bucket, cylindrical insulated water cooler, or rectangular box-type cooler), and type of sparging. For the Belgium Witt I sparged “on the fly,” using a device that I built, a T-style rigid plastic PVC with holes drilled on the bottom or tun side. I didn’t drill the holes accurately enough so I had some sparge water leak.
I sense that knowing the math conversion formulas is going to make it a lot easier for me to be consistent in the final product. I need to learn how to set my target original gravity (based on the type of grain I use), and then calculate water volume and malt weight to achieve target OG.
Next: math calculations to determine mash efficiency, and p/p/p.
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