Saturday, January 26, 2013

Dialing In Your Coffee Grinder

Brewing coffee presents a unique problem. It is extremely sensitive to a variable that most people have no way of measuring: extraction yield. Tea, by contrast, is tasty across a wide range of extractions, as evidenced by the fact that multiple steepings of the same tea leaves can produce delicious results. Bitter tea is over-strong, not overextracted.

So when you brew coffee, you're aiming at a very small target (18% - 22% extraction) which you have no way of measuring. To hit that target, most people rely on recipes handed down by a trusted source. But the problem with just following a recipe is that even if you can control water temperature, coffee dose, and brewing time, there's no way for a recipe to specify exactly how fine your grind should be. Typically, the recipe will specify, say, 'medium-fine' or 'the consistency of table salt', but this is far too inexact. Even a small difference in grind size can have a major impact on extraction yield. Furthermore, no grinder produces a perfectly even grind; every grinder produces a slightly different grind profile. What that means is that even if the average grind size is identical, the grounds produced by two different grinders will extract slightly differently.

Now, I do think recipes are a useful starting place, but everyone needs to dial the recipe in on their own grinder. The only way to do this, short of a coffee refractometer, is to rely on taste. So you should be able to taste underextraction and overextraction, and know how to correct for both. All this assumes that you're starting with good, fresh coffee, good water, and clean equipment.

1. Overextraction. This is relatively easy to taste. Overextracted coffee is harshly bitter, often astringent or solvent-like. If you want to know what overextraction tastes like, try boiling your coffee. Often times overextracted coffee will taste as if it is roasted darker than it actually is, because the bitter compounds that are extracted last are mostly dry distillates—burnt sugars and heavy maillard compounds—which are more concentrated in darker roasts. If your coffee tastes overextracted, use a coarser grind.

2. Underextraction. This is a bit more subtle. Underextracted coffee generally lacks sweetness and complexity, and sometimes has a tea-like flavor. Underextracted coffee is often described as being overly acidic or sour; this is not strictly true. Think about it: why would a cup with less extraction have more acid? However, it is true that acids extract more quickly than most compounds in coffee, so an underextracted cup may have a higher proportion of acids, which might lead to higher perceived acidity. If your coffee tastes underextracted, use a finer grind.

In order to dial-in your brewing technique, you need to make sure that you have control of all variables. That means weighing your coffee. Measuring by volume will make it much more difficult to dial-in your grind. Start with a middle-of-the-road dosage, say, 60 grams of coffee per liter of water (14g per 8 oz). If you're brewing manually (pour over, French press, Aeropress), you need to measure water temperature and brewing time. 200˚F is a good place to start for water temperature, but more importantly, be consistent with temperature and brew time.

Brew, taste, adjust grind if necessary, repeat. Take notes. Since overextraction is easier to taste, it can be a useful exercise to push the grind finer and finer until you taste overextraction, and then back off a bit. There are a lot of variables that affect coffee extraction, but most of the time you can get a decent cup just by manipulating the grind. In general, people worry far too much about the brewing device, and far too little about the grinder. Yes, you need an adjustable burr grinder, but once you have one, you can brew very good coffee even in a cheap automatic coffee maker—or a clean cotton sock—provided you know how to dial in your grind.

Friday, January 18, 2013

What's in a Beer?

The four ingredients in beer, as defined by Germany's Reinheitsgebot (beer purity law), are water, yeast, hops, and malted barley. Simple enough. What the Reinheitsgebot doesn't tell you is that there are dozens of kinds of malt, hundreds of varieties of hops, and thousands of strains of brewer's yeast. In what follows, I will try to explain what distinguishes the different yeast, malt, and hops that a brewer can utilize in crafting a beer. I'll leave water alone, since discussing water chemistry would require a whole post in itself, and is probably less interesting to most people.


Modern brewers have access to a huge variety of malts. All of them are produced from the same substance: raw, unmalted barley—which, to be honest, is pretty bland. However, by manipulating the way the barley is dried and cured, the maltster can produce a spectrum of bold flavors, such as toasted bread, nuts, caramel, dried fruit, smoke, coffee, and chocolate. On a more practical level, the malting process is necessary in order to produce the enzymes in base malts (alpha- and beta-amylase) that will convert the starches in the barley into sugars that the yeast can ferment. Virtually no modern breweries malt their own barley, but specialty maltsters like Briess produce very high quality products.


Unlike barley, the processing that hops undergo after they're picked is only meant to preserve the natural flavor of the hops, not to add any flavors. The variety of flavor that hops impart to beer is a result of their natural chemical composition. The flavor contributions of hops can be roughly divided into two categories: bitterness and hop aroma. Bitterness comes from the hop resinswhile hop aroma resides in the hops' essential oils. The alpha and beta acids that compose the hop resins are neither bitter nor soluble in their natural state. Brewers transform the alpha acids into isomerized alpha acids by boiling (desirable), while beta acids become bitter through oxidation (undesirable). Different hop varieties provide distinct flavors because of differing levels of the various hop resins and oils. European hops tend to be fairly mild, while some American, Australian, and New Zealand hops provide intense floral and fruity aromatics. Brewers add hops at different points in the brewing and fermentation process in order to manipulate the level and quality of bitterness and hop aroma that is present in the finished beer.


Yeast are what turn beer from a bitter, sugary liquid into the alcoholic beverage that we know. The type of yeast the brewer uses has a massive impact on the final product, because different strains produce different aromatic byproducts during fermentation, and different strains yield different levels of residual sweetness, or levels of attenuation. A highly attenuative yeast will leave very little residual sugar in the beer, resulting in a dry, crisp beverage, while a less attenuative yeast will produce a beer that is sweeter and more full-bodied. Yeast also vary in how quickly they flocculate, or clump together, which results in the yeast falling out of solution. Highly flocculant yeast are prized for producing clear beer in a short period of time, without filtration. Modern brewers have access to hundreds of yeast strains through yeast labs like White Labs and Wyeast.


What? The Renheitsgebot doesn't say anything about bacteria! However, lactic acid bacteria are essential for producing the delicious beverages known as sour beers. Styles of sour beer include: lambic, Berliner weisse, and Flemish sour ales. Sour beers usually contain a combination of lactic acid bacteria, the yeast Brettanomyces, and regular brewer's yeast. Brettanomyces can produce acetic acid in the presence of oxygen, but this is usually undesirable, so most acidity in beer comes from bacteria. Many strains of these bacteria are inhibited by hops, so sour beers are only lightly hopped. (Except lambic, made with large quantities of aged hops, which have lost most of their resins and oils.) Pediococcus works slowly (months to years) but can produce more acid than most lactobacillus strains.

Brewing With Lactic Acid Bacteria, Brian Nummer.
For the Love of Hops, Stan Hieronymus. Brewers Publications, 2012.
Hop Science III: Bitterness, Kristofer Krogerus.
Malting and Brewing Science: Hopped Wort and Beer, D.E. Briggs and James Hough. Aspen Publishers, 1982: p. 744
Malting Barley with Bob Hansen from Briess – BeerSmith Podcast 35
The Prokaryotes: Vol. 4, Falkow, Rosenberg, Schleifer, Stakebrandt, eds. Springer 2006: p. 344.
Yeast, Chris White and Jamil Zainasheff. Brewers Publications, 2010.

Sunday, January 6, 2013

Vermont Breweries

This past weekend I visited my cousin and his fiancé in northern Vermont, and toured some local breweries. Vermont has the highest brewery-to-person ratio of any state, with roughly one brewery for every 25,000 people. Large, mediocre breweries like Long Trail and Magic Hat distribute their beer throughout the Northeast, but the very best Vermont beer can only be purchased in-state.

Perhaps the epitome of Vermont breweries is Hill Farmstead. Hill Farmstead is located in a remote corner of Vermont known as the Northeast Kingdom, where 74% of the roads have been rated as being in 'poor' or 'very poor' condition. The land on which the brewery sits has been in the brewer's family for eight generations, and most of Hill Farmstead's beers are named after his ancestors. The demand for their beer has so outstripped supply that bottles have been illegally auctioned off for hundreds of dollars on eBay.

I didn't make it out to Hill Farmstead, but I did manage to try several of their beers at a great pub in Waterbury called Prohibition Pig. Holger Danske, a brown ale with Beech-smoked malt, was a perfect pairing for savory food. Susan (hopped with Riwaka, Citra, and Simcoe) was an excellent example of what seems to be an emerging style for Vermont's IPAs: juicy, full of resinous and tropical fruit aromas, and nearly opaque with unfiltered hop debris. But the star of the show was Arthur, a saison heavily hopped with both American and European hop varieties. This is the first really hoppy Belgian-style beer I've particularly enjoyed. So good.

If there's one beer that Vermont is known for, it's Heady Topper, a double IPA from The Alchemist. Since The Alchemist's main brewery was destroyed in the floods of 2011, they now brew Heady Topper exclusively. Heady Topper is sold in cans, but generally sells out the day it arrives in stores, so I visited their cannery to taste a sample. Like Susan, Heady Topper is cloudy in appearance and features tropical fruit notes, but seemed to have a firmer, more defined bitterness and a bit more malt flavor. Their proprietary yeast strain, Conan, gives the beer a distinct peach aroma. Homebrewers across the country are currently working themselves into a frenzy trying to clone this beer.

Lawson's Finest Liquids is Vermont's smallest commercial brewery, but has garnered an outsized reputation. Unfortunately, they're not open to the public, but I did get a sip of their Kiwi Double IPA at Prohibition Pig. The beer doesn't contain kiwis, but is hopped with New Zealand's Nelson Sauvin and Pacific Jade hops. Pretty damn good. I also found a bottle of Lawson's at Winooski's Beverage Warehouse. It was Paradise Pale Ale, a dry-hopped pale ale brewed with 100% Vienna malt, which gave it a deep amber color and a nice nutty note in the finish.

After visiting Prohibition Pig, we found ourselves just down the street from Magic Hat, so we stopped in. Samples were generous, and they had some cool artwork. We also stopped at a few breweries I hadn't previously heard of: Fiddlehead was featuring an excellent hoppy imperial brown ale, though their IPA wasn't anything special. Switchback offered a nice tour, but fairly uninspiring beer, unless your thing is subtle, malty pale ales. Vermont Pub & Brewery had a number of interesting beers, including a sour-mashed raspberry beer (which wasn't sour enough), and another sour called Tulach Leis, which had a nice brett aroma but a weak finish. Unfortunately, we were a day early for the release of their bacon rauchbier.