Monday, July 20, 2015

Hop Blending, or Why There Is No Perfect IPA Recipe

I brew a lot of hoppy beers. Most my beers call for 8-14 oz of hops per 5 gallons of beer.  Given that the flavor of these beers is dominated by hops, the particular blend of hops used is paramount. I think it's generally agreed upon that—while single-hop IPAs are interesting and can be quite tasty—almost all the best IPAs contain a blend of hop varieties. But what is the best strategy for selecting varieties to pair, and what proportions should one use?

Looking at the hops used in some of the most acclaimed IPAs, some patterns do emerge. IPAs created more than 10 years ago generally use a blend of so-called 'C' hops: Cascade, Centennial, Chinook, and Columbus (Nugget gets an honorable mention here). IPAs from the past 10 years have many new varieties of hops to work with. In these IPAs, Simcoe and Amarillo are frequently paired: as in Alpine's Duet, Ballast Point's Sculpin, Ithaca's Flower Power, Russian River's Pliny the Elder and Pliny the Younger, and Surly's Furious.

With more hop varieties being released every year, hop blending has become increasingly complicated. Given this complexity, I decided to begin my experimentation with just a few hop varieties. But even then I ran into difficulty.

To be specific, I had a recipe for a heavily-hopped amber that I was quite fond of. It contained Nugget and Cascade as flavoring hops, and Simcoe and Amarillo as dry hops. I brewed a lot of this beer, quickly ran through my hop reserves, and had to order another pound of Amarillo. When I brewed the same recipe with the new Amarillo, the beer was starkly different. The beautiful passionfruit aroma had taken on a harsh tinge of garlic. This aroma was evident in the smell of the raw Amarillo hops themselves.

High quality hops are not a commodity. I have found a significant degree of variation in the aromatic characteristics of the hops I have received. Which meant that my quest for an ideal blend of hops was doomed from the start. This realization discouraged me for quite a while, but I have found hope in a new approach to hop blending.

Instead of designing recipes based on the characteristics that particular hop varieties are supposed to have, I brew based on what the current batch of hops I'm using actually smell like. Is this batch of Columbus particularly aromatic? If so, I may use it as a dry hop. If not, I'll use it as a bittering hop. I pay particular attention to the level of sulfuric compounds. At moderate levels, these compounds can provide a pleasant fruity pungency (grapefruit, blackberry, passionfruit), but at higher levels they conjure garlic and cat piss. In general, newer hop varieties (especially Amarillo, Mosaic, Simcoe, Summit, and Citra) contain higher levels of sulfur, but there is a great deal of variation even within a single variety. One of my main objectives in blending is to achieve the right level of sulfuric aromatics.

All this talk of aromatic compounds is, I'm sure, an oversimplification. My main point is that, given the level of variation in hop aroma within each hop variety, brewers should pay more attention to what their hops actually smell like, and less attention to what hops a particular recipe calls for.

Sunday, March 23, 2014

Brett Sour (3/9/14)

My latest sour beer uses the same quick-souring technique as my last two sours, sometimes known as sour-worting (a variation on sour-mashing). I mash the beer normally, but rather than boiling the wort after mashing, I cool it to 112˚F, add 1/4 lb of crushed 2-row barley, and maintain that temperature for 3-7 days. During this time, the native lactobacillus present on the barley produce lactic acid. The temperature inhibits the growth of spoilage bacteria and yeasts. After souring, I boil the beer normally, with a modicum of hops. The boil kills virtually all bacteria, so from this point onwards, the beer is no longer spontaneously fermented. I pitch a pure-culture strain of yeast and ferment according to that yeast's needs.

The only tricky part about this whole shuffle is keeping the beer at 112˚F for most of a week. I've gone through a few very kludgy solutions to this problem, including placing a keg in a (somewhat) temperature-controlled water bath. My current system is a bit more manageable, consisting of a lamp, a temperature controller, and an unpowered refrigerator. The temperature controller tells the lamp when to turn on and off, and the refrigerator provides insulation. It's basically an incubator. I can maintain my desired temperature (in this case, 112˚F) to within 2˚F for as long as I want.

For this particular sour, I decided to use Brettanomyces as the only alcoholic fermenter. Brettanomyces ("Brett") is an entirely different species from brewer's/baker's yeast. For most brewers and winemakers, it's a scourge to be eradicated, but it also produces characteristic and sought-after flavors in Belgian and American sour beers.

I used a strain of Brett (White Labs Brett Brux Trois) isolated from a bottle of Drie Fonteinen lambic. It has gained something of a following among some American brewers for use in 100% Brett beers. It is markedly less funky (barnyardy, smoky, spicy) than most strains of Brett. Instead, it produces tropical fruit aromas with just a hint of funk.

The grains in this beer (2-row, English medium crystal, flaked barley) would, with a normal ale yeast, produce a fairly typical American pale ale. However, the combination of lactic bacteria and Brett overwhelms the flavor of the malts. The hops are even less distinguishable.

Brewed 3/9/14.

3/16/14: Boiled with 0.3 oz of Columbus. Added Brett Trois. Fermented at 72F.

3/20/14: Medium-high acidity, fruity, slightly savory aroma. Low bitterness. Overall my best sour yet.

Kegged 4/6/14: More Brett aroma. Balanced and fruity.

Saturday, December 28, 2013

Destructive Myths: The Dissolved Oxygen Hypothesis

Part I: The Argument

There are a lot of myths and unfounded maxims surrounding the proper preparation of coffee and tea. Most are harmless, or, at worst, detrimental to beverage flavor. But one such myth has resulted in a massive waste of energy and water. I refer to this myth as the dissolved oxygen hypothesis.

The dissolved oxygen hypothesis states that, when brewing tea, one should always use freshly drawn water, and never reboil water in the kettle. The justification given is that water that has previously been boiled has less dissolved oxygen (DO). The result is that many tea drinkers are wasting enormous amounts of energy by dumping leftover hot water from their kettles.

The dissolved oxygen hypothesis rests on two premises: (1) that once-boiled water contains more dissolved oxygen than twice-boiled water; (2) that dissolved oxygen improves the flavor of tea. Both premises are demonstrably false.

Boiling itself does not remove dissolved gases. It is the change in temperature or pressure that affects the amount of gas that a liquid can hold (i.e., the solubility of a gas in a liquid). Solubility decreases as temperature increases. Assuming normal atmospheric pressure and composition, water at 0˚C can hold a maximum of ~15ppm DO, while water at 50˚C can only hold ~5ppm. Once the water reaches 100˚C, solubility is zero. Therefore, if you've brought water even close to a boil, you've removed virtually all the DO. What this means is that neither once-boiled nor twice-boiled water contain significant levels of DO, refuting premise (1).

Studies (Faust & Aly 1998, Pangborn & Bertolero 1972) have found that the level of DO in drinking water does not have a significant impact on its taste. It seems likely that the folk belief that DO improves water flavor results from the fact that running water (e.g., streams) is generally preferred to stagnant water (e.g., lakes), and is also higher in DO.

In principle, DO could soften the tannins in tea, just as decanting a bottle of red wine does. However, decanted wine contains much more DO, on account of its lower temperature, and wine is usually allowed to breathe for at least 15 minutes, compared to the 1-5 minutes that tea steeps for. Furthermore, tea drinkers can control the level of tannins in their cup via manipulation of steeping time, water temperature, and water/tea ratio. In short, a well-brewed cup has no need of oxidation.

Therefore, both premises that lead to the dissolved oxygen hypothesis are false. (1) Tea water does not contain a significant amount of DO, and even if it did, (2) there's no evidence that the level of DO has any impact on the flavor of the tea.

All argumentation aside, I simply cannot tell the difference between tea brewed with once-boiled water and tea brewed with twice-boiled water. I've done the tasting blind, more than once. In part, this post is a challenge to any believers in the dissolved oxygen hypothesis: try a blind triangle test. If you succeed in distinguishing tea made from once- and twice-boiled water, let me know.

All this is not to say that water is unimportant. Water is important. Alkalinity is important. Salt content is important. Minimal iron content is super important. Dissolved oxygen is not important.

Part II: Confounding Results

Here's the twist: I can easily distinguish between fresh tap water and water that has been boiled for an extended period of time. In the process of investigating the dissolved oxygen hypothesis, I boiled a small quantity of filtered water for 5 minutes, then refrigerated it until it matched the temperature of my tap water. I then drew some fresh filtered water, and tasted the two, blind.

There was a clear taste difference between the boiled and freshly drawn water. The freshly drawn water had a clean, crisp finish, while the boiled water had an off-putting twang to it. This was not a hard distinction to make.

I repeated the test using a different pot to boil the water, to make sure there weren't any contaminants in the first pot. Same result: the boiled water tasted worse than fresh water.

Given that DO does not have an impact on water flavor, what could explain the flavor impact of the 5 minute boil? Boiling can have a number of effects besides removing dissolved oxygen. It can also remove chlorine as well as concentrate dissolved minerals by reducing the water. But my water filter removes all detectable chlorine, and the short boiling time did not reduce the amount of water by an appreciable amount. Boiling can also remove calcium and bicarbonate ions (by precipitating temporary hardness), but my water is quite soft, and I have never noticed any scaling (which would indicate precipitation of temporary hardness.)

The only plausible explanation I can think of is that boiling the water would also have removed any dissolved CO2. Dissolved CO2 will form a small amount of carbonic acid, which can significantly lower the pH of very soft water (like mine). The fresh water would then have a lower pH than boiled water. Since most consumable liquids are at least slightly acidic, this might explain why the fresh water seemed to have a clean, crisp finish compared to the boiled water. This explanation predicts that less of a difference would be evident if more alkaline water were used, because alkalinity buffers against changes in pH.

Why then wouldn't removing dissolved CO2 from water also affect tea flavor? Well, the amount of dissolved CO2 in tap water is not enough to have a significant impact on the pH of any solution much stronger than pure (soft) water. A full explanation of this phenomenon would require an in-depth discussion of pH buffering, but this is why the pH of a brewer's mash depends much more on the alkalinity than the pH of the source water.

Even if small amounts of dissolved CO2 did affect the flavor of tea, heating water close to boiling will remove virtually all dissolved CO2, just as it removes DO. For brewing tea, coffee, or any other hot beverage, dissolved gases are irrelevant.

Faust & Aly, 1998. Chemistry of Water Treatment, 2nd Edition. p. 114 (
Pangborn & Bertolero, 1972. Influence of Temperature on Taste Intensity and Degree of Liking of Drinking Water. Journal of the American Water Works Association.

Thursday, November 21, 2013

Lichtenhainer (9/13/13)

Certainly the most obscure style I've ever attempted, Lichtenhainer was an extinct German beer style that combined the tartness of a Berliner weisse with the savory Beech smoke of a rauchbier. Before modern kilning technology emerged, many beers exhibited smoky flavors from the wood used in the malt's drying process. Likewise, before careful sanitation became standard, most beers were mixed fermentations, with both lactic acid and alcoholic fermentations proceeding in parallel. Smoked sours, therefore, would once have been quite common, though they're now virtually nonexistent.

Lichtenhainer was one of the last remaining examples of a smoked sour beer. The last continuously-produced Lichtenhainer was brewed in 1983. The style has since been brewed by at least one German brewery and one American brewery, though neither are easily available.

For this beer, I used the same souring technique I used on my last sour: 5 days of spontaneous lactic fermentation at 112˚F. This time I did the lactic fermentation in a CO2 purged keg, in order to further inhibit aerobic spoilage bacteria. I then performed a 5 minute boil and fermented it with US05 American ale yeast.

Like my previous sours, this beer reached typical levels of attenuation. It's neither as dry as a traditional lambic, nor is it as sweet as sweet lambics or most Flemish sours. The acidity is aggressively lemon-like. The beech smoke plays a supporting role, expressing itself as a rich, savory finish. Unusual, to be sure, but delicious and surprisingly drinkable.

ABV: 5.5%
IBUs: 10
OG: 1.055
FG: 1.012

Malts Mashed Amount % Max Pts.
Smoked 5 50% 37.00
2 Row 5 50% 36.00
Hops/Additions Amount Time AA%
Spalt 0.75 60 4.0%

Tuesday, October 22, 2013

Simplicity Stout (5/15/13)

Stouts are a great way to use strange ingredients. Since they're so strongly flavored, there's little risk of overpowering the flavor of the beer. As a result, they've become a kitchen sink beer for American (and Scandinavian) brewers. First came the coffee stouts, then the chocolate stouts and vanilla stouts. Then came spiced stouts, fruit stouts, mint stouts, even bacon stouts. Right now the highest-rated Russian Imperial Stout on BeerAdvocate is Three Floyd's Bourbon Barrel Aged Vanilla Bean Dark Lord.

This time, I wanted to take the opposite approach. No weird ingredients, no aging on wood, just an intense, full-bodied beer with a prominent roasted grain flavor. I did use five different types of barley in this recipe, but each plays a vital role. The two row is a fairly neutral base malt; the chocolate malt and roast barley together produce intense and complex roast flavors; the English crystal adds sweetness to balance the bitter roasted grains; finally, the flaked barley adds body. Since aroma is often where regular stouts are lacking, I also added a decent amount of Nugget as an aroma hop, which adds pleasant floral notes.

Had a stuck mash and didn't get very good efficiency. I did a long boil and added a bit of extract to make up for it.

First tasting 10/21/13: Good aroma, balanced flavor profile, excellent mouthfeel. Just enough alcohol in the aroma to add complexity. Subdued but noticeable esters. This beer is great now, but I expect it to continue to improve for at least a year. I will have trouble making it last that long.

ABV: 8.2%
IBUs (Tinseth): 40
OG: 1.082
FG: 1.019

Mash adjustments: 2.5 grams slaked lime, 5 grams calcium chloride
Sparge adjustments: 1 drop 88% lactic acid
Mash temp: 154
Mash length: 60 minutes
Efficiency: 60%

Yeast: Wyeast 1098 British ale yeast (close relation to WLP007)
Starter: 4 liters
Pitching temp: 65F
Max temp: 74F

Malts Mashed Amount % Max Pts.
2 Row 15 79% 36.00
English Medium Crystal 1 5% 34.00
Chocolate 1 5% 28.00
Roast Barley 1 5% 25.00
Barley (flaked) 1 5% 32.00
Other Fermentables Amount
Max Pts.
DME 2.25
Hops/Additions Amount Time AA%
Magnum 1 60 14.0%
Nugget 2 5 10.0%

I performed a 90 minute boil to reduce volume.

5/21/13: Gravity is 1.019.
6/4/13: Bottled to 2.3 volumes of CO2.

Friday, October 4, 2013

Iced Coffee, Part 2

Last year, I wrote a post detailing my attempts to brew good iced coffee at home. I intended to follow up on it once I'd done some more experiments. Then summer ended and I stopped drinking iced coffee. Pretty much the same thing happened this summer, but I've made some progress. Iced coffee, for me, will never compare to hot coffee, but I've grown to appreciate both cold brew and chilled iced coffee.

For cold brew, I like a ratio of 1 part coffee to 12 parts water (i.e. 83 grams per liter). If you cold brew in the refrigerator, รก la Barismo, use a medium (cupping) grind. If you cold brew at room temperature, use a medium-coarse (press) grind. (Room temperature coffee will melt the serving ice quicker, and hence become diluted faster.) Both methods produce good results in 12 - 24 hours.

Filtering cold brew can be challenging, especially if you make a lot of it. The first step is to remove the large particles of coffee with a metal chinois, china cap, or tea strainer. But even extremely fine metal filters will not provide an acceptable level of clarity by themselves. For a polishing filter, there are three options: paper, cloth, or synthetic. Paper filters are easy to find, but clog up very quickly. Organic cotton filters are a better option if you can find them, but they're still fairly slow and require careful cleaning. My preferred filtration medium is food grade monofilament nylon, so long as it's rated 20 microns or smaller.

In Peter Giuliano's influential post on iced coffee from last year (Japanese Iced Coffee), he argues against cold-brewed coffee, on the grounds that it is (allegedly) underextracted, oxidized, and lacking in aromatics. I'll discuss these objections individually, then look at what alternatives to cold brewing exist.

Giuliano claims that low brewing temperatures necessarily result in underextracted coffee. It's true that most cold brew is underextracted, if its extraction yield is calculated according to the traditional formula (Extraction[%] = BrewedCoffee[g] * TDS[%] / CoffeeGrounds[g]). But this is only true because cold brew is usually made as a full immersion brew. As Vince Fedele has argued, calculating extraction yield for immersion brewing requires a different calculation (Extraction[%] = TotalWater[g] * TDS[%] / CoffeeGrounds[g]). Making this adjustment puts cold brew back in the proper range of extraction, if performed properly.

Giuliano also claims that long brewing times result in oxidized (i.e., stale) coffee. In my experience, cold brew does certainly become oxidized, but not nearly as quickly as hot brewed coffee, because oxidation occurs more slowly at lower temperatures. Still, I prefer to drink cold brew within 12-24 hours of brewing. Even with refrigeration and nitrogen flushing, more than a couple of days is pushing it. Of course, many people enjoy the woody flavors that result from oxidized cold brew. (The entire success of coffee stouts is built on this fact.)

Giuliano's preferred iced coffee brewing method, which he calls the "Japanese iced coffee method", involves brewing hot coffee via pour-over directly onto ice. I've tried this technique dozens and dozens of times over the past couple of years. I've tried varying grind, dose, ice/water ratio, and water temperature. I've tried both V60s and Chemex, as well as immersion brews poured through a paper filter. Every single time, I get a unpleasant musty aroma.

Now that I'm using an espresso machine again, I've noticed a very similar aroma when making espresso over ice. I think, therefore, the most likely source of the unpleasant aroma is temperature shock. I've been reluctant to believe that temperature shock really exists, because no one I know of has given it an adequate scientific explanation. But I've found that by allowing the coffee to cool somewhat before adding ice, the unpleasant aroma can be minimized.

Upon re-reading Giuliano's post, I was struck by this passage on volatility:

"Cooling the coffee quickly, though, reduces volatility dramatically.  This effectively locks the ephemeral volatiles (like floral and fruit notes) into solution until the coffee is warmed again.  This happens on the coffee’s way down your throat (sorry to get graphic here), which sends a punch of beautiful volatile aromatics through your retronasal cavity to your olfactory receptors.  And that explains the olfactory-flavor punch of brewed-hot-quickly-cooled Japanese-style iced coffee."

Is it possible that the aromas that I perceived as unpleasant and musty are the same that Giuliano describes as 'floral and fruit notes'? My, how tastes vary! What it comes down to, I think, is this: Cooling coffee very rapidly results in a distinctive aromatic profile not found in cold brewed or slow chilled coffee. The degree to which this aromatic profile is desirable depends on both the coffee and consumer.

Since I have not yet found a coffee that I enjoy brewed directly over ice, I prefer to slow down the chilling process somewhat. My basic method is this: brew coffee at a 1:10 ratio (100 g/l). After brewing, cover and allow the coffee to cool slowly, until it's below 150˚F (66˚C). Then add ice and stir until the coffee is under 50˚F (10˚C). Strain the coffee over fresh ice and serve. The whole cooling process should take 5 - 10 minutes. For large batches, an ice bath may be necessary to hit this time frame.

There are two standard objections to this technique. The first objection is that the increased coffee/water ratio will decrease extraction yield, making the resulting coffee underextracted. The premise of the argument is true, however, this effect can be compensated for by using a slightly finer grind, as in bypass brewing, and/or by adding water at a slower rate.

The second, more serious, objection is that allowing the coffee to cool slowly allows an unacceptable amount of oxidation to occur. Oxidation is largely responsible for the staling of brewed coffee, and oxidation occurs much more rapidly at high temperatures. Therefore, the slow cooling to 150˚F involved in the above method means that more oxidation occurs than if the coffee were chilled immediately.

My response: When I brew hot coffee, I don't drink it when it's over 150˚F, because at that temperature it's impossible to taste all its subtleties. (Also, I don't like to burn my tongue.) I (gasp!) let it sit for a few minutes before tasting. If the above objection were valid, it would imply that all the hot coffee I'm drinking is stale. But the fact is, even at high temperatures it takes a little while for oxidation to reach a noticeable level—at least 20 minutes. Therefore, there's no reason to believe that allowing coffee to cool somewhat before adding ice will make it noticeably oxidized, provided the coffee is served soon after chilling.

Other iced coffee resources (not all of which I agree with):

Friday, August 9, 2013

Mash-up Quick Sour

Over the course of my first three attempts to brew a Berliner weisse, I've learned a few things about brewing quick (i.e., less than 6 months to complete) sour beers—having had to dump two of my first three batches. They weren't poisonous, but they also weren't worth drinking. Sour beer is the one style of beer in which even the most skilled brewers still routinely have to dump batches.

Lesson #1: If you want to make sour beer fast, induce a lactic acid fermentation before alcoholic fermentation. Alcohol seriously inhibits lactic acid bacteria, as do hop acids.

Lesson #2: If you're souring prior to fermentation (and don't have a completely sterile environment), keep the temperature above 110˚F (43˚C), in order to inhibit spoilage bacteria that produce nasty compounds like butyric acid (think vomit, parmesan cheese). Lactobacillus is thermophilic and can handle the heat. Above 115˚F, however, lactic acid bacteria are much slower to produce sourness. Above 140˚F, most bacteria are dead or inactive.

Rather than continuing my attempt to brew a perfect Berliner weisse, I've decided to switch my efforts to attempting the most delicious quick sour I could brew, borrowing techniques from both Belgian and German brewing traditions. My current approach is as follows:

Mash and lauter normally, but instead of boiling the wort, allow to cool to 112˚F (44˚C), then add a handful of crushed 2-row and cover with plastic wrap. Maintain this temperature until the desired level of sourness is reached, sampling daily (2-7 days is a reasonable window). The beer will taste a little bit more sour after most of the sugars have been fermented into alcohol, but it's a minor difference. If the beer starts to smell "off", raise the temperature to 122˚F for 30 minutes. After souring, boil the beer with hops, then cool to 70˚F and pitch your favorite ale yeast. Add fruit if desired after the yeast fermentation is complete.

The main challenge with this technique is keeping the beer at 112˚F. My current set-up consists of an electric heating element and a digital temperature controller, but I've also heard good things about the fermenter heat wraps that homebrew stores sell. If you have little money and much time, intermittent low heat from a stovetop might work. But that would also be a huge waste of energy.

Even though this technique involves spontaneous fermentation, it produces a very clean sour beer. The fact that the beer is boiled after souring also means that almost no bacteria are present in the finished beer, so contaminating your non-sour beers is not a concern. If you want a funkier sour, adding brettanomyces to secondary is always an option, but cross-contamination then becomes a concern again. If you want a sweeter sour, my preferred method is to add a fruit syrup to the glass when serving, as is traditional for Berliner weisse.


OG: 1.056 (pre-souring, pre-boil)
FG: 1.008
ABV: 5%?
IBUs (Tinseth): 15

Water adjustments: 5 grams of calcium chloride
Mash temp: 151F
Mash length: 60 minutes
Efficiency: 75%

Yeast: WLP545
Pitching temp: 70F
Max temp: 71F

Malts Mashed Amount % Max Pts.
2 row 8 74% 36.00
Barley (flaked) 0.75 7% 32.00
English Medium Crystal 2 19% 34.00
Hops/Additions Amount Time AA%
Cascade 0.75 60 6.0%