Wednesday, September 26, 2012

Hoppy Red Rye Tasting

Over the last decade, hops varieties seem to be getting trendier. For a long time Cascade was the go-to hop for American beers, then Centennial made a run, the combination of Amarillo ad Simcoe is a modern classic, and now everyone wants Citra. There are dozens of new varieties being bred, and one of them will be the next big hit. It is hard not to get swept up in these new varieties when they impart bold new flavors heretofore not possible in hoppy beers. However, with so many other varieties out there finding new combinations of existing varieties is another way to create unique flavors.

Hop quality is a bigger deal than most homebrewers give it credit. It is of enough importance that many larger craft breweries send someone to the Yakima Valley and Hallertau to evaluate the harvest each year. As homebrewers we are often left with what remains, unable to evaluate the product until we open the package on brew day. There are some brewers who think of hop varieties like a commodity (Simcoe is Simcoe), when in fact you might get a more exciting hop character in an IPA from terrific Centennial rather than poor quality Citra.

Rather than relying on the supply chain to take care of the hops from the time they are harvested in the fall until when I am brewing, I’d rather buy the varieties I know I’ll use in bulk as soon as they are released, and store them myself. Doing this also saves money and avoids situations where those prized varieties disappear six months before the new harvest.

The Cascade for this Hoppy Red Rye was from Indie Hops, hopefully part of a wave of suppliers catering to craft brewers (and hopefully homebrewers) - who appreciate hops for more than just their level of alpha acids. I paired it with Sterling, originally bred as an American grown replacement for Saaz, but it is more powerfully aromatic and brings some fruitiness to compliment the spice.

A glass of RED Rye IPA.Hoppy Red Rye

Appearance – When I first brewed this beer I was sure it was too dark. When I poured the first sample from the tap it looked too light. Luckily after the yeast settled it ended up a beautiful garnet red. The head is dense, sticky, off-white, and gorgeous.

Smell – The nose is multifaceted, toasted malt, citrusy hops, and red berries. The hops smell fresh, sticky, grapefruity, but they aren’t over-the-top pungent. The berry-malt is wonderfully aromatic.

Taste – Solid bitterness at first, with some residual sweetness, and then lingering hops. Well balanced, although I tend to like my hoppy beers somewhat drier. The toasted-caramel malt comes through, not doughy or bready. Hops meld with the malt, citrus, hay, herbal; they need to be more intense to market as an IPA variant. Slight ethanol note on the finish.

Mouthfeel – Medium-heavy body for a moderate alcohol beer. Solid carbonation, about right.

Drinkability & Notes – Of all of our “first attempts” at Modern Times recipes, this may be the most successful. However, it doesn’t have the special something that makes Founders Red’s Rye such a perfect beer. Dialing back on the malt, and up on the hop aromatics will get us there though I suspect.

Monday, September 24, 2012

Rumble Barrel Belgian Strong Dark Recipe

Two 5 gallon Balcones barrels.I’ve never aged a sour beer in a small (< 50 gallon) barrel because I’m wary of them. Small barrels are usually about same price as full-sized barrels, and thanks to their high surface-to-volume ratio they quickly impart a potent oak flavor, allow a higher rate of oxidation, and more rapid evaporation. However, when Balcones Distillery offered to send me two of the five gallon American oak barrels they age their spirits in I knew I’d find something to age in them.

Aging clean beers in small barrels has a number of advantages for homebrewers. Filling one requires a single batch, so the chances of introducing unwanted microbes (as we did with our first group bourbon-barrel-aged beer) is much lower. I switched to eight gallon buckets for primary fermentation last year; these larger fermentors allow me to brew six gallon batches, large enough to fill the barrels to the brim with fermented beer. Head space accelerates oxidation by allowing the staves at the top of the barrel to dry, so partial filling is not a viable option.

Crushed grain, and two bags of dark candi syrup.For some advice I emailed Doug Dozark, of Peg’s Cantina, brewer of some very well regarded beers aged in 5 and 15 gallon whiskey barrels. He suggested checking the oak level imparted by first use five gallon barrels after just three weeks, compared to two to three months for 15 gallon barrels. By comparison beers aged in full-sized barrels often age for six to twelve months before packaging.

The first barrel I’ll be filling (later this week) previously held Rumble, which Balcones distills from Mission figs, wildflower honey, and unrefined cane sugar. Those flavors made me think of a dark Belgian ale. I wanted something strong enough to stand up to the rapid extraction of oak and booze, Belgian Dark Strong (aka Quadrupel) fit the bill. It didn't hurt that I really enjoyed the batch of Pomegranate Quad I brewed in February with my neighbor, which I only kept a six-pack of for myself.

While this batch is technically a test-batch for Modern Times (we're on the hunt for a head brewer), it is more of a proof of concept than a recipe we can actually scale up. I used Valley 2-Row Pale Ale Malt as the base (also included in my Dubbel last year), which being malted on a small scale in Massachusetts probably won’t find its way into our Southern California mash tun. To the boil I added a pound each of D-90 and D-180 from Candi Syrup Inc, which I don’t believe is available yet on a craft brewing scale. I fermented the dense wort with East Coast Yeast Belgian Abbaye (ECY09), which isn’t available in commercial pitches. Not to mention aging in that small barrel (we'd need 186 of them to age a single brew on a 30 bbl system)!

A big beer needs a big starter, stir-plate helps.I do not plan to clean or otherwise sanitize the barrel before filling, the previous 124 proof resident took care of that. Oak is nearly impossible to sanitize with chemicals anyway because its porous texture allows microbes to penetrate deep into its grain. Heat is the best option, but even with near-boiling water it is difficult to sanitize a barrel completely because wood is such a good insulator. In addition, hot water would rinse away much of the residual spirit character.

Balcones Whisky barrels, the other one they set, can be purchased through some homebrewing stores. There are a number of other nano-distillers located around the country that sell their used barrels. In the DC area, Catoctin Creek’s 30 gallon rye barrels are a common sight at brewpubs. Tuthilltown in New York sells a variety of barrel sizes on their website that previously aged their whiskey.

Doug warned me against refilling barrels, but I’m hoping that I can rack the first beer out of the barrel, give it a quick rinse with really hot water to remove any trub, and then refill it immediately with a second batch. My planned second fill (a cinnamon/vanilla spiced imperial porter) will take a bit longer to extract adequate oak flavor, and should receive a softer spirit character. After each barrel ages two clean beers, I’m planning on splitting a 10 gallon batch of sour brown between them. I’m interested to taste the results, but I’ll be prepared to move the sour beer into carboys for additional aging if the oakiness becomes too potent before the beer is ready to bottle.

Rumble Barrel Belgian Strong Dark

Recipe Specifics
Batch Size (Gal): 6.25
Total Grain (Lbs): 20.13
Anticipated OG: 1.079
Anticipated SRM: 28.9
Anticipated IBU: 26.5
Brewhouse Efficiency: 66%
Wort Boil Time: 120 Minutes

59.6% - 12.00 lbs. Valley Pale Malt
24.8% - 5.00 lbs. German Vienna Malt
3.7% - 0.75 lbs. CaraMunich Malt
1.2% - 0.25 lbs. Crystal 120L
0.6% - 0.13 lbs. Carafa Special II
5.0% - 1.00 lbs. D-90 Candi Syrup
5.0% - 1.00 lbs. D-180 Candi Syrup

1.50 oz. Hallertauer Tradition (Pellet, 6.00% AA) @ 90 min.

0.50 Whirlfloc @ 15 min.
0.50 tsp Yeast Nutrient @ 15 min.

East Coast ECY09 Belgian Abbaye

Water Profile
Profile: Washington, DC

Mash Schedule
Sacch Rest - 60 min @ 151 F

9/6/12 Made a 1.25 L starter for my stir-plate. Didn't see much activity for 24 hours, but it looked and smelled fine after that.

9/8/12 Brewed by myself

No water adjustments.

Undershot pre-boil gravity slightly, and overshot my pre-boil volume. 9 gallons @ 1.052, 1.058 with the addition of the candi syrup (1 lb each D90 and D180). Extended the boil 30 minutes longer to further concentrate the wort.

Chilled to 68 F, pitched entire starter, hit with 30 seconds of pure oxygen, left at 64 F to ferment.
Strong fermentation by 12 hours Quickly threatened to blow-off in the 8 gallon bucket.

After 36 hours, from pitching, increased ambient to 66 F since fermentation already appeared to be slowing. 24 hours later, with the fermentation appearing nearly complete, I moved the fermentor to 74 F ambient to finish.

9/29/12 Down to 1.018, a bit sweeter than expected, but it should be perfect with the oak. Racked into the Balcones Rumble barrel, filled to the brim. Replaced the hard bung. The wood provided nucleation sites that caused the beer to foam when I checked on it a couple hours later. Left at 70 F ambient to age for a couple weeks.

10/21/12 Bottled with 2.75 oz of table sugar, aiming for 1.9 volumes of CO2.  Solid, but not overpowering barrel character. Tastes pretty good.

3/15/13 Turned out really well, nice blend of barrel and base beer characters.

Monday, September 17, 2012

Hoppy American Pale Ale Tasting X 2

How important is yeast strain selection for the perception of hops in the finished beer? Some yeasts, especially highly flocculant strains, have a tendency to strip hop compounds (including bitterness) out of the wort. This is the reason that some brewers suggest waiting until after fining or filtering a batch to add dry hops. Neutral-flavored moderately-flocculant American ale strains like 001/1056 are a safe choice if you want the yeast to simply stay out of the way.

There is another school of thought however. Some brewers select yeast strains that provides an estery character that blends with the hops creating a more powerful/complex aroma. There are breweries that opt for Belgian ale or saison strains (Charlevoix Dominus Vobiscum Lupulus), while others choose English ale strains (Ithaca Flower Power). The right combination can be transcendent, but the wrong pairing of hops and yeast can be close to undrinkable.

In a world where every brewery has access to the same malts and hops, having a house yeast strain is one way to give your beers a distinct character. At the moment, the highest rated hoppy beer on BeerAdvocate that isn't brewed by Russian River is The Alchemist’s Heady Topper. For me John Kimmich's hop saturated beer lived up to the hype (unlike the bottle of Kern River Citra DIPA I opened last week) with a wonderfully pungent hop aroma mixed with a peachy ester that seemed yeast derived.

“‘The heart of the beer is my private strain of Conan ale yeast,’ John explained. ‘It produces very distinct apricot and tropical fruit esters, but you have to know how to handle it, how to draw the character out.’ It took years of tweaking to get the age and the generation of the Conan yeast just right so it would produce the flavor John wanted.” via Sip this world-class beer straight from the tallboy

In July I cultured Conan from a fresh can of Heady Topper, starting it in the can before building it up on my stir plate. I pitched the yeast it into an extra gallon of wort from my Hoppy Pale Ale. Hoping for the best, but given the proprietary nature of the strain hard to know for sure what temperature to target.

So here is the side-by-side tasting of the same wort fermented by the two very different ale strains (note that in addition to the yeast difference, the WLP001 fermented potion also received a substantial dose of keg hopping.)

Hoppy Pale - WLP001

America ale fermented West Coast pale ale.Appearance – Nearly clear, golden beer. Pours with a large head, but it quickly settles to a dense, creamy white cap. Pretty lacing and retention.

Smell – More malt aromatics than I expect in a hoppy American beer. The Victory malt really comes through, with fresh baked bread and crackers. Plenty of hops too, pine and citrus, fresh and bright. It is an interesting combination, but not the balance I had envisioned.

Taste – The flavor is a good mixture of malt and hops, but I intended it to be hop first with a malt background. The hop flavor is really saturated with the hop bursting, hop standing, hop backing, and dry hopping. Good classic West Coast hop character: orange, pine, slightly dank, balanced. Firm bitterness, without lingering too much. Clean fermentation.

Mouthfeel – Decent body for a session beer, solid carbonation.

Drinkability & Notes – Like most of the other first attempts we’ve made at recipes for Modern Times, the results are good, but not exactly what we wanted. A few tweaks to the malt bill (removing the Victory) and hop bill (considering some Southern Cross in place of the Columbus) and we’ll be closer to the target.

Hoppy Pale - Conan

Alchemist's Conan yeast fermented West Coast pale ale.Appearance – Pours with a similar color to the standard version, but considerably hazier (thanks to bottle conditioning and storage at room temperature). The head doesn’t have the same creamy texture, and retention is much weaker despite higher visible carbonation.

Smell – As expected it lacks the big hop nose, thanks to the lack of dry hopping. Unexpectedly however, the strong maltiness is also absent. Both are preset, but are subdued. Taking the lead is an assertive fruity/spicy yeastiness, with peach and clove most prominently.

Taste – The flavor is a bit drier, which accentuates the bitterness. As with the nose, the yeast character plays a big role. The moderate West Coast hopping melds well with the yeast character. The bready malt comes through more on the palate than it did in the nose. As it warms I detect a slightly funky edge, hard to tell if it is from a stressed fermentation, or something that got into the yeast culture.

Mouthfeel – The medium-high carbonation is a bit more than I prefer, but it doesn’t come across as over-carbonated. The extra bubbles make the body seem lighter, although maybe that is just higher attenuation.

Drinkability & Notes – I was under the impression that the Alchemist’s house strain “Conan” was English in origin, but the phenols give this beer a Belgian slant. I actually enjoy this variation, but without dry hops the yeast overpowers even the considerable late/post boil hopping.

Monday, September 10, 2012

Stolen Microbes - Lambic with 3 Fonteinen Dregs

Probably the best tasting I have been to.What do the Belgian gueuze producers still have over the upstart American sour beer producers? For me, the best gueuze has a balance of acidity and funk that I have yet to taste from even the best American brewers (although some are getting very close). My favorite, 3 Fonteinen, produces beers that have a softness and drinkability that I prefer over the brash acidity of some American and Belgian sour beer brewers. 3 Fonteinen gueuze isn’t bland, on the contrary Armand Debelder's blending creates layers of flavors from only four ingredients (Pilsner malt, raw wheat, aged hops, and water) that are unmatched by every seven-malt-fruited-double-barrel-aged beer I have tasted.

How is this possible? I give some of the credit to the slow, spontaneous fermentation. Breweries that rely on wild microbes living in the oak of their barrels have a wide variety of different cultures, which are grown and selected organically over time (the barrels that make the best beer are retained and used to inoculate new barrels). This is a huge advantage over breweries that have a single commercial house culture that is pitched to sour all of their sour beers. Luckily American breweries like Jolly Pumpkin, Hill Farmstead, Allagash, and others are taking this route as well.

The cooled wort next to the 3 Fonteinen dreg starter.The best Belgian gueuze blenders also have more experience blending sour beers. Most of them only have one base beer to deal with, which allows them to draw from a wider selection when crafting each blend. The longer time they let their beers age is a big factor as well, not many American sour beers spend more than 18 months in oak, while 3 Fonteinen just released Golden Blend a blend that includes four-year-old lambic.

While I’ve been happy with the results produced by the local DC wild microbes that I cultured last year, I wanted to steal some microbes directly from Armand’s beers (more than just a single strain of Brett). My chance came when my friend Dyan invited me to a going-away 3 Fonteinen blowout tasting he threw for himself. That night the six of us went through a total of 11 beers (the four Armand’4, Hommage, Golden Blend, 2009 Oude Gueuze, Vintage 2002 and 2007, 2005 Doesjel, and Straffe Winter). While not every beer was remarkable (although most were), the Armand’4 Lente (spring) may have been the most astonishing gueuze I have tasted. It was fresh, with bready malt, bright grapefruit, flowers, and anchored by a gentle enveloping funk.

In addition to contributing the uncarbonated Doesjel, I brought a bomber containing 12 ounces of sterile starter wort that I used to harvest the dregs from the four seasonal Armand’4 (the last of the lambic brewed at 3 Fonteinen not lost in the 2009 warehouse temperature incident), plus the fresher of the “Vintage” bottles (a blend of Armand’s favorite barrels) and the excellent 2009 Oude Gueuze. I allowed the microbes to grow in the bomber for a few weeks with an airlock attached, to avoid the acetic acid production that occurs in the presence of oxygen.

Racking the lambic wort to the fermentor.Rather than a complex turbid mash that I have executed for batches of lambic in the past, I decided to follow Dave Pyle’s wort production process, a simple single infusion. In addition to malted wheat, I added the extra pound of flaked spelt I had on hand for a recent batch of saison. I also shortened the boil from the traditional three-plus-hours, but I retained the well-aged hops.

Rather than force chilling the wort, as I have done for every batch of beer I have ever brewed, I allowed it to cool slowly, open to the air. My goal was to introduce microbes that are active early in spontaneous fermentations, but do not survive the long aging (e.g., enteric bacteria and oxidative yeasts). I didn’t want the cooling beer to sit on the large amount of spent hops, so I scooped them out of the wort during the last few minutes of the boil. I left the uncovered brew pot outside until the wort cooled enough to stop steaming, before bringing it down to my air-conditioned barrel room. 18 hours later with the wort chilled to the ambient 66 F, I pitched the 3 Fonteinen dreg starter. Fermentation took three days to show the first signs of activity, but was so active that it was still blowing off four days later. Like all of my sours it will be awhile before I can judge the results of this process, but after a month the beer already has some acidity and a complex fruity flavor.

Coincidentally the article I wrote about six months ago about American wild ales, and at-home spontaneous fermentation, was published in the September issue of BYO. I’ve got a couple more articles coming in the next few months (“Other” Fermentations, followed by American brewed dark lagers), so if you want to read those, subscribe with this link (so I get half the subscription cost)!

The first page of my BYO article on American Wild Ales.Lambic #6 - Drie

Recipe Specifics
Batch Size (Gal): 5.25
Total Grain (Lbs): 9.50
Anticipated OG: 1.052
Anticipated SRM: 3.2
Anticipated IBU: 11.8
Brewhouse Efficiency: 76 %
Wort Boil Time: 130 Minutes

60.5% - 5.75 lbs. German Pilsener
28.9% - 2.75 lbs. Wheat Malt
10.5% -  1.00 lbs. Flaked Spelt

3.00 oz. Willamette (Whole, Aged Four Years, ~1.00% AA) @ 125 min.

3 Fonteinen Guezue Dregs

Water Profile
Profile: Washington, DC

Mash Schedule
Sacch Rest - 75 min @ 157 F

Starter made from dregs from the four Armand'4 Oude Gueuzes, Golden Blend, and 2009 3F Gueuze.

Brewed 8/11/12

Decided against a turbid mash. Batch sparged, reached 170 F after the infusion.

Collected 8 gallons of 1.034 runnings. Hops were ~4.5 year old Willamettes that had been open for about 18 months. Used a strainer to remove most of the hops during the last 5 minutes of the boil. Allowed to cool uncovered outside to 150 F. Left in 66 F barrel room uncovered for 18 hours.

Racked to 6 gallon BetterBottle., shook for a minute, then pitched the 12 oz starter (smelled fruity, tart, light funk).

Fermentation was slow to start, but by the third morning there was a thin white skin, and by that night full-blown fermentation. 24 hours later the beer began blowing off vigorously.

8/2/14 Bottled all 4.5 gallons with a couple grams of rehydrated Pasteur Champagne yeast and 4 1/8 oz of table sugar (aiming for 2.6 volumes). Added 2 cones each Simcoe and Amarillo to the first and last two bottles.

2/26/15 Completely worth the wait! Really great lemon and funk, very 3F-like.

Thursday, September 6, 2012

Tasting Four Blended Sour Beers

All four blended beers side-by-side.Somehow I’d forgotten that it had been almost a year since I convinced my friends Alex, Peter, and Nathan to spend a day blending and bottling my beers. I don’t think it is that hard to make a B+ sour beer from a single batch of wort, fermented in single fermentor, but doing better than that takes a lot of luck even for the best brewers in the world. The only way to consistently get terrific is to become a master of blending multiple batches together.

Rather than post detailed tasting notes for each of the four blends, I thought I’d give a few notes on what I think about the beers, how they compare, and what I learned. Tasting notes of each of the base beers are linked from the formulas

A glass of Nathan's sour blend.Nathan's
33% Dark Saison III
33% Irma
33% Apple Brandy Golden

Appearance – Reddish-brown, thin tan head.
Aroma – Waxy, red berries (Irma), slightly boozy, and mild vinegar (Apple Brandy Golden).
Taste – Balanced acidity (not much acetic) with some sweetness. It is slightly wheaty in the finish.
Mouthfeel – Medium bodied for a sour beer. Medium-low carbonation.
Drinkability – I like the flavor more than the aroma, overall a solid sour that grew on me as it warmed.

A glass of Alex's sour blend.Alex's
50% Apple Brandy Golden
30% Berliner Lambic
20% Dark Saison III

Appearance – Burnt-orange, very poor head retention (and none of these beers are great).
Aroma – Similar to Nathan's with its hints of acetic, but it has more oak. Cleaner with less overt fruitiness.
Taste – The acidity is big and bright, only slightly acetic. The same balance as a good Flemish red, minimal funk.
Mouthfeel – The oak adds more tannins than the other beers have.
Drinkability – A more drinkable version of a Flemish red, crisper and drier.

A glass of Pete's sour blend.

66% Berliner Lambic
18% Buckwheat Amber
16% Apple Brandy Golden

Appearance – The palest of the group, brilliantly golden.
Aroma – The cleanest of the aromas, fresh hay, apple, and slight perfume.
Taste – Bright snappy acidity, slightly stodgy malt, dry, I think it needs a boost from something.
Mouthfeel – The crispest of the bunch. Similar carbonation to the rest, but it would benefit from more.
Drinkability – I like this considerably more than Berliner lambic straight (we put half onto cherries too).

A glass of my sour blend.Mine
40% Buckwheat Amber
40% Dark Saison III
15% Berliner Lambic
5% Apple Brandy Golden

Appearance –The darkest of the blends, brown with red highlights.
Aroma – Big earthy buckwheat honey, almost as strong as in Dark Saison III, but it is muted somewhat.
Taste – The flavor diverges from the dark saison, with a rounder, toastier flavor. Moderate sourness.
Mouthfeel – The fullest of these beers, and the lowest level of carbonation.
Drinkability – I like this quite a bit more than the straight Saison III. It has a better balance, and is easier to drink.

So what did all of that blending and subsequent tasting teach me?

There are definite thresholds where certain flavors cross from undetectable to prominent very quickly. My blend, despite only containing 7% more of the Dark Saison III than Nathan's, had a much stronger buckwheat honey aroma. Similarly it can take relatively small additions to correct perceived issues as with Pete's augmentation of the Berliner lambic.

Especially when bottle conditioning trying to figure out how the beer will change is one of the most challenging tasks.  I initially really liked Nathan's blend, but as time has gone on Alex's has caught up to and maybe passed it. It makes me appreciate the defense Lauren Salazar (New Belgium's blending guru) gives for the decision to pasteurize the "Lips of Faith" bombers of La Folie.

However, despite the challenge and mystery of the blending arts, I think all four of us did a very good job on our first real attempt at blending these beers. None of the results are perfect, but I think all of them are better than at least some of their component beers. Hopefully I find an excuse to do something similar again when I have another round of sour beers ready to be bottled.

Tuesday, September 4, 2012

Do you skim off the foam as your wort comes to a boil?

Nathan in action, skimming the wort for one of our soleras.No - 77%
Yes - 22%

When I announced this poll a month ago on both my Twitter and Facebook, I received a few confused reactions along the lines of “Why would anyone skim the foam as their wort comes to a boil?” Despite less than a quarter of homebrewers responding that they do, I think there are a few advantages that are enough to justify this small/optional brew-day chore.

The more protein the wort contains, the more foam forms on the surface of the wort as the temperature approaches 212F (wheat beers tend to produce an especially dense mousse-like foam). While some people refer to the foam as “hot break,” traditionally/technically this term refers exclusively to the flocks of protein seen floating in the boiling wort (for a good picture of what this looks like, see my batch of spelt saison). I’m sure the Germans have some cool word for the foam, but it hasn’t been given a special name by American homebrewers.

Skimming reduces the chance of a wort boil-over in two ways. First, removing the coagulated protein foam reduces the sudden rise at the onset of the boil that within seconds can lead to wort bellowing over the sides of the kettle and onto your burner. Skimming also forces you to stick around the kettle as the wort comes to a boil, so you’ll be there to turn down the heat if necessary. Alternatively you could add an anti-foam product like Fermcap-S (which I don’t care for) or use a spray bottle of water to deflate the foam.

The result of skimming the foam as my lambic wort came to a boil.Skimming removes break material that would eventually settle out in the kettle or fermentor. You’ll also skim any bits of husk/grain that make it passed your grain filter-bed. Not a big deal if you do a good vorlauf, but it is especially valuable if you BIAB (brew in a bag) or if you cannot recirculate. While no professional breweries that I am aware of skim, their brewing systems are much more efficient than most homebrewing rigs when it comes to getting clear wort into the fermentor.

Skimming does not have a negative impact on the head retention of the finished beer in my experience. This is because proteins are only capable of coagulating one time (Don't believe me? Try to return a hard boiled egg white to its uncoagulated liquid state.) so the proteins you scoop from the wort would not have assisted in head formation. However, if you use a mesh strainer that serves double-duty for anything other than skimming wort, then make sure it is scrupulously cleaned because it doesn’t take much oil to seriously disrupt head stability.

I don’t skim every single batch. For example, when I add first-wort hops skimming would remove the hops before the boil. This rule also serves for any batch where a solid ingredient is added to the wort post-mash, but pre-boil. Otherwise I’m a skimmer (unless someone posts a good counter-argument in the comments).