Wednesday, October 10, 2012

Brewing Primer Part 5 of 12: Sparging

Sparging is the process by which all the residual sugars remaining in the mash are washed out of the grains and into the boil kettle. There are two main methods of sparging, batch sparging and fly sparging.

Batch Sparging

Because I batch sparge, I end up having to lauter again during each sparge. Once I have the mash tun empty after lautering, I close my spigot and add hot water. I double batch sparge, so I do two separate sparges. Normally I'll add about 8 quarts of 180F water for my first batch, and 8-10 quarts of 180F water for my second batch. This help to get the mash up towards 167F, known as "mash-out" which halts enzymatic activity, lowers viscosity of the wort, and assists in washing out as much sugar as possible. For each batch, I dump in the water, stir up the grain bed, then begin the lautering process again before proceeding to allow the rest of the wort into the boil kettle. Once the sparging is complete I can begin to boil the wort.

Although I use a bazooka screen, that isn't the only way to filter out grains. Some homebrewers will use plastic coolers as mash tuns due to their insulating capabilities, and will rig together grids of copper tubing with little holes in them to act kind of as a large screen. Another common method is to use a false bottom above the drain spout. Grain collects on top of the false bottom and the slots cut into the false bottom allow wort through without allowing grain particles to pass.

Fly Sparging

Fly sparging is a continuous sparge. Once lautering is complete and the grain bed has begun to filter, hot water is added from above at a rate equal to the outflow of wort from the mash tun. This can be done in a number of ways, but generally requires some sort of setup to spread the sparge water equally across the surface of the grain bed. As more and more sugars are sparged out of the grain bed, the pH of the wort runoff rises and the specific gravity falls. At some point (I've read at an SG of 1.010 or 1.019) the low specific gravity and high pH cause tannins to be leached out of the barley hulls, leading to astringency in the wort and thus the beer. So the stopping point for sparging is whenever the gravity of the wort begins to get too low.

Advantages and Disadvantages of Each Method

The advantage of fly sparging is that it is more efficient than batch sparging. Because water is being spread equally on the surface of the grain bed, all the sugars throughout the grain bed are being washed out, and there is no channelling taking place. With batch sparging there is often channelling of some sort. In my mash tun I notice much of the wort draining around the edges of the tun, not necessarily evenly throughout the grain bed. That being said, for homebrewers the efficiency gains from fly sparging are probably only on the order of a couple percent. While small gains can be commercially significant, for a homebrewer they're probably not worth the effort.

The advantage of batch sparging is that it's easier than fly sparging, and it allows you to use a precise amount of water. Rather than trickling water through until the runoff reaches a certain gravity, batch sparging allows me to calculate my water needs in advance. I know that my grains soak up about 0.130 gallons of water per pound, and I know how much wort I lose by boiling, so know that I need about 8.25 gallons of wort into my boil kettle. Mash Water + Sparge Water - (pounds of grain * 0.130) = 8.25 gallons. So if I have 10 pounds of grain and use 5 gallons of water in the mash, I know that I need to use about 4.5 gallons of water in sparging. I suppose I could heat 4.5 gallons of water and slowly fly sparge it, but for me it's easier and far less time consuming to batch sparge. I'd rather lose a couple points of efficiency than an hour out of my day.

Brewing Primer Part 4 of 12: Lautering Wort

I'm not sure why I decided to break lautering and sparging into two separate articles, but what is done is done. Lautering comes from the German verb läutern, meaning to clarify or purify. It is the process by which the wort (which is what the water is called once it is full of maltose and other sugar compounds) is clarified. While it is still in the mash tun, there are large amounts of flour, barley hulls, and pieces of grain. Naturally you don't want these in the boil, you just want to boil the liquid, and ideally you want it to be as clear as possible.

The barley hulls will help to act as a natural filter, keeping out larger particles, but it takes a while for the grains and hulls to compact enough to become an effective filter bed. Liquid can come through but most solids are trapped. Until then, the wort should be recirculated back through the mash until the wort runnings come out clear. Hulls are also only your secondary filter, you still need a primary filter. I use a bazooka screen, which is a little mesh tube that threads onto the inside of my spigot fixture. The photo shows what the screen looks like inside my tun. When I open up the spigot on my mash tun I reserve the first half gallon or so of wort in a separate pot, after which time the wort is free of debris and relatively clear. After a few minutes the mash tun has emptied and I can begin to sparge.

Brewing Primer Part 3 of 12: Mashing Grain

Once your grains are crushed, it's time to mash them by adding water. There are a whole bunch of different things to think about when mashing grains. In no particular order, they are:

  1. Water Temperature
  2. Mash Thickness
  3. Mineral Content
  4. Mash pH
  5. Types of Mashing

Before I start explaining these topics, let me just say that this is just a layman's description of the mashing process. If you want more detail, I would recommend reading John Palmer's section on mashing in How To Brew, or Braukaiser's "Theory of Mashing," both of which will give far more information than I can convey in a single blog post. And if you're really interested, you can start googling and find excerpts from brewing textbooks and brewing journals, which I find absolutely fascinating.

1. Water Temperature

But back to mashing. Water temperature is the most important thing most homebrewers will have to deal with. Remember that malted grains have already begun the process of starch modification, that is, the conversion of starch into sugar. Roughly 20% of the starches in malted grains have already been converted. The malting process also activates enzymes present in the grains, which are necessary to continue the process of starch conversion.

The most important temperature range for the mash is the sugar rest, or sacchirification rest, where amylase enzymes are activated to convert starches into sugars. The most common temperatures range from about 150F to 158F, depending on the type of beer brewed or the maltiness desired. Generally the lower a sacchirification temperature used, the drier a beer will be due to more simple sugars being produced, while the higher the temperature the maltier the beer will be due to longer chain sugars being produced. Beer yeasts prefer single chain sugars (glucose) but can also digest maltose (two joined glucose molecules) and lager yeasts can digest maltotriose (three joined glucose molecules.) Once you start getting into maltotetraose and higher, beer yeasts no longer have the ability to digest quite as many of those sugars, if any at all. You can make quite a good beer using just a single temperature rest between 150F and 158F, and in fact I've done so, but I've moved to various different mashing procedures.

What I do now is dough in (add water to my crushed grains, or vice versa) to reach a mash temperature of 100-104F. I calculate my mash infusions by using the mash infusion calculators at TastyBrew. Doughing in allows the grain to take up water without forming dough balls. If I were to do a single rest at 155F, I would have to heat water to around 170F, and the resulting mash at 155F would be above the gelatinization temperature of the barley starch, resulting in dough balls throughout the mash. Unless those dough balls are broken up, none of the grain inside the ball will be accessible to water, and thus those starches will not convert to sugar, leading to lower mash efficiency. So I like to start by doughing in. This temperature also happens to be within the temperature range of the acid rest, which activates the enzyme phytase to lower the pH of the mash, which I'll explain later.

The next step would be a protein rest, generally only used when using poorly modified malt or high amounts of high-protein malts or raw adjuncts such as wheat, corn, rye, etc. Protein is what forms the beer's head, so too much of a protein rest breaks down the proteins and leads to poor head retention. Too much protein can lead to chill haze, haziness in the beer when cold, but I drink my beer unfiltered so I don't really care about haziness or cloudiness. Even when I brew with wheat, spelt, and rye I generally don't worry about including a protein rest unless I'm doing a decoction mash (which I'll also explain later.) The protein rest temperatures are around 120F to 135F.

Once you get above 140F you start to activate the amylase enzymes. Beta amylase is most active between 140F and 150F, and alpha amylase above 150F. As the temperature increases, enzymes active at lower temperature are denatured and cease to be active, so by the time you get up into the 150s amylase enzymes are just about the only ones still active. To determine whether or not your mash has fully converted, it might be helpful to do an iodine test. What I do is take a small spoonful of wort from the top of the mash and put it into a glass. I put one drop of iodine in the glass: if the mash is fully converted, the iodine will remain yellowish; if not, it will turn blue. If it remains blue, you need to mash for a little longer. Generally a mash time of around one hour is sufficient to convert all the starches to sugar. But that is partially dependent too on...

2. Mash Thickness

The thickness of a mash is expressed in the number of quarts per pound of grain. A thickness of 0.75 quarts of water per pound of grain is enough to soak the grains, but there won't be too much water left over to do much else. One quart of water per pound of grain is very thick and even up to 1.5 quarts of water per pound of grain is considered a relatively thick mash. Once you start getting up to 2 or 3 quarts per pound of grain, you start to get into the thin range. The thicker a mash is, the quicker the starches will convert; the thinner a mash is, the longer the conversion takes.

It makes sense if you think about it because each unit of grain can produce only a certain finite amount of enzymes. The more water you have, the more spread out the enzymes are, and thus the longer it takes them to travel around and convert all the starches. I generally start off with a thickness of 0.75 to 0.8 for my doughing in, and add boiling water to try to reach 1.5 to 1.8 for my sacchirification rest(s).

3. Mineral Content

Mineral content is something I never really though about when I started brewing. It was only after I started trying to brew light-colored beers and wondered why they always were kind of pink-hued that I began to look into my water quality. The types of minerals present in brewing water will have an effect on the color and taste of beer. Some of the important minerals and ions include magnesium, sodium, calcium, carbonates, chlorides, and sulfates. It helps to find out the various mineral levels your municipal water has. If you're on well water you'll probably have to get your water tested by a lab.

Once you know the levels of the various compounds, there are spreadsheets and calculators available online into which you can input those numbers. I think the spreadsheet I use was created by John Palmer, and inputting my numbers I found that my beers were going to emphasis hoppiness over maltiness, and that my water was most ideal for amber to brown-colored beers. However, if I wanted to brew Pilsner or Kölsch, one gram of calcium chloride added to the mash would make sure that I could get that nice straw color without any pink or other off hues.

4. Mash pH

For the quickest starch conversion, the pH of the mash needs to be in a range between 5.2 to 5.5. Obviously water starts at a pH of 7.0 or higher, but adding malt to water reduces the pH. The lighter the malt, the higher the pH of the mash will be, while the darker the malt, the lower the mash pH will be. In distilled water, wheat will result in a pH of around 6.0, Pilsner and 2-row around 5.7, Vienna around 5.5, Munich around 5.4, and roasted malts around 4.7. Thre is an EZ water calculator spreadsheet circulating on the internet that aids in calculating mash pH, or you could just buy a pH tester. I've never felt the need to do so, and I doubt that either I or anyone who's tasted my beers would probably taste the difference if I decided to start fooling around with mash pH.

Since mineral content of water has an effect on mash pH, different regions or cities specialized in different types of beers, depending on the type of water they had. Cities with hard water would brew darker beers, since the pH-lowering effects of dark and roasted malts would counteract the alkalinity of the water. Cities with soft water such as Pilsen could brew lighter beers, although with the higher pH of the lighter malts they would have to begin their brews with acid rests in order to achieve their optimal mash pH. My brewing water isn't particularly hard, but I do use a short acid rest just to make sure that I'm (hopefully) working within an optimal pH range.

5. Types of Mashing

If I had to take a guess at the type of mash most frequently used by homebrewers, I would have to imagine it would be a single infusion mash. Hot water is added to crushed malt to reach a single target temperature within the sacchirification temperature range. It's relatively easy to do.

I normally use a multi-step infusion mash, doughing in to 100-104F and then adding infusions of boiling water to reach various predetermined temperature steps such as 145F, 153F, 158F, etc., depending on the beer I'm brewing.

There is also direct heating, in which heat is added directly to the mash tun in order to reach the various steps. This is often only feasible with thin mashes, otherwise the direct heat could scorch the grains.

Finally there is decoction mashing, in which large portions of the grain are removed from the mash, brought to a boil, and then returned to the mash to reach the various temperature steps.

There is probably much more to talk about in terms of mashing procedure, but this hopefully should provide the basic outlines, with some of the links up above providing much more detailed information.

Oat Beer: Part 1

Oat beer has a very bad reputation, due to stories going around about how astringent it is, and how it caused sailors to mutiny when they were forced to drink it. But surely nowadays with the advances in malting technology and with hulled oats available at every grocery store in the country this shouldn't be the case anymore, right?

Well, there's only one way to find out, so I decided to create another 1-gallon test batch of oat beer. The grist was 60% Weyermann Vienna malt, with the other 40% being rolled oats from the grocery store. I did a cereal mash with the oats to ensure that the starches were fully available, then mashed in at 100F and added boiling water to get to 155F. Efficiency was lower than I expected, but I still haven't gotten everything dialed in completely on these 1-gallon batches. I used part of my S-04 yeast cake from my pumpkin beer to ferment this oat beer, and in a few weeks I should see how it tastes. Hope it's not too bad.

Monday, October 1, 2012

Pumpkin Beer

When life gives you pumpkins, make pumpkin beer. We've had volunteer pumpkins popping up in our garden for the past couple years, kind of infuriating since we had hoped they were zucchini, but hey, sometimes you just gotta run what you brung. I hadn't planned on making pumpkin beer until someone put the idea in my head last week. So I figured, why not try a pumpkin beer? The reason I had initially rejected the idea was that I had visions of pumpkin flesh clogging up my siphons when transferring. But then I realized that pumpkin beer would actually be better off with pumpkin in the mash rather than post-boil.

And the pumpkins are just the right size for a small batch of beer, so I decided to go ahead and try a one-gallon test batch. I cut a small, elongated pumpkin in half and roasted it for 45 minutes at 350F. The next day I cut the flesh out and popped it into the mash tun. I ended up getting 24 ounces of innards and mashed that with 2 pounds of Weyermann Vienna. The problem with these small batches is that water calculation ends up being way off. I got almost 3 gallons of wort into the boil kettle, and still had at least 2 quarts of wort stuck in the mash. Oh well, just meant I'd have to boil longer.

I first wort hopped with 0.5 ounces of Spalt and ended up boiling for 2.5 hours before I finally got down to around a gallon of wort. The wort ended up super dark and caramelized, so I'm very interested to see how it tastes. Yeast will be an S-04 yeast cake from my previous 1-gallon experimental batch, and this'll be the 5th generation for this particular batch of yeast. My plan is to get to 9 generations before I dump it. More to come in a few weeks once I get this bottled and carbonated.

Oh, and no spices in this one; I want pumpkin beer, not pumpkin pie beer.

Smoked Beers: Grätzer

The many hours of smoking grain back in March paid off in a big way when I decided to brew this Grätzer in late April. Grätzer is a smoked beer from eastern Germany that received its smoked character from the wood that was burned to create heat to dry the malt. Traditionally it was a wheat beer, but I decided to smoke 4 pounds of raw spelt and use two pounds of Weyermann Light Wheat to provide the enzymes for starch conversion. I had calculated that that should provide just enough diastatic power for conversion, but that didn't work out. I ended up having to go up to 4.5 pounds of Weyermann Light Wheat and even that wasn't enough. The mashing process took several hours as I periodically tested wort samples with iodine to see if the starches had fully converted. The mash ended up taking 4.5 hours, and even then it wasn't fully converted. The mash was a decoction mash, which probably wasn't a great idea when starting off with only two pounds of malt.

According to my brewing notes, the sparge was very slow and stuck toward the end, and I had so little wort that I had to shorten the boil from 90 minutes to 60. Even with that I still ended up with only 4 gallons of finished beer, but what a beer it was. The photo doesn't do it justice, the color is light as straw, lighter than any commercial light lager. This was also the first beer I ever fermented with a hefeweizen yeast, in this case Danstar Munich. I wasn't a huge fan of it at first, but it's beginning to grow on me. We'll see how it stands up once I brew with WB-06.

The only smoked beer that most people are familiar with is Schlenkerla, which is a lot darker. Even Brauerei Spezial Rauchbier is much darker than this one. So when you first see the color you're not expecting the smoke, and it does hit you. Not as ham-tasting as Schlenkerla, definitely milder like Spezial, but quite noticeable. And the wheat beer yeast has kind of a bubble gum type flavor to it, which makes for an interesting combination. My parents weren't huge fans of it, but everyone else who tried it loved it.

I still have several bottles left of this, but the smokiness has gotten a little less pronounced over time. It's a great summer beer, only 4% ABV, hopped to 40 IBU with 2.5 ounces of Saphir, which is a very subtle noble hop which is terrible for lagers but wonderful for wheat and rye beers. If I ever were to do this beer again, I think I'd smoke malt as well as raw grains, and I'd definitely try to smoke much more than four pounds, so that I could do multiple batches of smoked beers.