brew day: Get The Acorn

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It will probably be the last brew day of October, and it may well be the last brew day under the open sky before the looming winter of 2013/14 ushers operations into the garage and kitchen. It will be a day to play hooky and eat lustily of the tacos of bachelorhood, even if only for an afternoon, and over the sink so I don’t have to wash dishes later.

It will be a west coast IPA with West Coast IPA, riffing on the recipe for Russian River Blind Pig in Mitch Steele’s IPA. It will have some well-loved old friends – Rahr 2-row, Amarillo, Simcoe – and some new blood too: Polaris for the bittering power, EXP 5256 standing in for CTZ and Cascade where called for in the Blind Pig bill.

Sidebar: I first smelled EXP 5256 at this year’s Craft Brewer’s Conference and was very stricken. I remember the sample at the HopSteiner table as being pinier and more roundly fruity than the pack I ended up getting months later, but I think it’ll still do very nicely here – very pungent and dank, a bit cat-pissy, a bit musty, with some of that Summit-like garlic-and-orange citrus and overtones of wild grapes.

Anyway, IPA: it’s America’s beer now. This was reinforced for me at the GABF last week, not only through its – surprise, surprise – ubiquity, but through the realization that, tasting through some admittedly excellent domestically-brewed continental lager styles and saisons, the battle for global supremacy in those styles is still contested with the brewers in those beers’ native countries; but that citric, dank, Colorado-dispensary-stinky, hoppy expression is still best spoken in a nasal accent that just talks louder to make itself understood, and it’s not ordering from the menu and it wants a hamburger with plain yellow mustard.

Now I need to get back to the sink and finish lunch, then go see a mash about denaturing some amylase enzymes.

Get The Acorn IPA
Target OG: 1.057


  • 96% Rahr 2-row pale
  • 3% Caramel 60L
  • 1% CaraPils


  • 152F for 75′
  • 170F for 10′


  • Polaris (pellet, 21.6% aa) at 60′ to 49 IBU
  • Amarillo (whole, 9.5% aa) at 30′ to 12 IBU
  • Blend of equal parts Amarillo, Centennial, Simcoe, and EXP 5256 at 0′, at a combined rate of 11 grams/gallon


  • Chill to 65F, O2 and pitch with Wyeast 1217 West Coast IPA (2nd generation, washed & re-propped)
  • After attenuation is complete, dry hop with more Amarillo and EXP 5256 at a rate of 3 grams/gallon and 4.25 grams/gallon, respectively, for an additional 10 days

43 thoughts on “brew day: Get The Acorn

  1. I pretty much took the summer off from IPA’s, so with the falling leaves, I am looking to return to them soon. A RIPA sounds pretty good about now. It’s good to try new and different and then remember where you started.

  2. Good Day Mr. Dawson:

    I hope this doesn’t sound stupid, but can you skunk a brew during the boil if you are out brewing in the bright sunlight?

    Since I am in California, I have the privilege of brewing outdoors year round. However, I’ve always boiled with the boil kettle out of direct sunlight (e.g., in the shade, or under the overhang of the deck) lest I get a skunked wort before it even sees the chiller.

    If it doesn’t make a difference, I would love to finally brew in the bright sun!



    • Hey Tom,

      That is an excellent question, and I’m not sure I have a pat answer. I have boiled outside for years and never had a problem.

      To recap for myself as much as anything: “skunking” is the photolysis of isohumulone – UV or visible light breaks the isomerized hop acid molecule, and the resulting radical reacts with a sulfur compound to make the mercaptan 3-MBT, which smells like skunk spray, and which has an extremely low flavor threshold in beer (obviously). The hop acids have to be isomerized in a boil before they can be light-struck this way; and various sources, anecdotal and otherwise, state that this reaction can happen very quickly given adequate exposure to strong enough light, so it seems like I should be getting at least some skunky worts under sunny skies, but as far as I know, I’m not. It’s possible that some combination of the opaque brew kettle, mechanical agitation of the wort, the ongoing isomerization during the boil, or other factors are helping protect it.

      Fix, Lewis, DeClerck, and other texts I consulted all describe the chemical reaction as above, but more accurately and eloquently; they don’t always mention a process or stage associated with this photolysis, but when they do it’s in the context of packaging or serving (i.e., green or clear glass bottles, clear glassware).

      A commenter in a thread on this topic over at referenced this article, which states that riboflavin is a necessary helper molecule for the degradation of isohumulone by visible light; riboflavin can be synthesized by yeast – so if it can only happen after the start of fermentation, that could explain why I’ve gotten away with boiling outside; although my understanding is that riboflavin is also contributed by malt …

      Finally, this amazing blogger makes the point (read down through the comments) that, while a highly-hopped, all-malt beer would have all the needed raw materials to produce a godawful mess of 3-MBT, it would also have a larger amount of robust native flavor to help cover up the skunk (he or she also advocates limiting exposure to light during production … so there).

      • I’m a bit late to this, but may I still interject?

        1. Exposure of wort to 400-500 nm light, which is blue/green visible light, is only part of the problem here. Several factors affect the efficiency of the photochemical cleavage of the isomerized AA’s en route to 3-MBT (e.g. extinction coefficient of the chromophore, quantum yield of photolysis for this reaction, intensity of ambient light source, time of exposure, etc.), but I think one reason why folks don’t usually see “sun-struck” wort while brewing outside is that the local concentrations of relevant starting materials are low. The other player in the skunking process, at least if you believe Fix, and the references contained in Principles of Brewing Science, is hydrogen sulfide (i.e. H2S). While dimethylsulfide (i.e. (CH3)2S) is indeed produced during wort production, H2S, as far as I can tell, is an artifact of the fermentation process. Offending bacterial microflora (e.g. Zymomonas) are usually responsible for H2S production in ales, but lager yeast can also metabolize some wort constituents to H2S. It takes two to tango, and while you may get photolysis in a backyard setting, the fate of the resulting isoprenyl radical is not likely 3-MBT.

        2. I’m assuming most folks aren’t using colorless or green glass BK’s during wort production. The majority of the wort is protected by non-permissive materials, like SS, or aluminum. Only a thin layer of wort is exposed to the sun at any given time. For sure, the boiling process is a dynamic one, but all things considered, the likelihood of 3-MBT production during a vigorous boil is low. Consider the following: Due to it’s volatility, any H2S that may be present in the wort is being flashed off before it has a chance to react.


        • Anytime, DK! I always find your insights into the biochem stuff valuable.

          That all makes sense to me, given the extant literature’s focus on protection in packaging vs. production – higher s/v ratio of bottles and growlers vs. boilers, opacity of the production equipment, volatilization during the boil, lower levels or absence of precursors & catalysts …

      • I want to echo Dan’s thoughts here (opaque boil kettle + turbid wort = reactions at air-work interface where they will be immediately driven off) and suggest a simple experiment to test: can you skunk your hydromoeter sample? I’ve never thought to try but am going to do this next time.

          • The iso-alpha molecules present would certainly be way more exposed at a tiny fraction of batch volume in a light-permeable container (test jar, bottle, growler, glass, etc.) than at full batch volume in a boiler. I’m not sure where that puts the sulfur compounds in all this …

            An interesting side experiment would be whether or not wort from a lightly modified continental lager malt would be more prone to pre-fermentation skunking than, say, a pale ale malt-based wort. Would wort from a concentrated, partial-volume boil be at less risk than one from a full-volume boil? Would the SRM of the wort have an effect – e.g., stout less susceptible than an American lager?

            • Interesting. So if it is indeed possible to skunk a pre-ferment hydrometer sample, we could assume that 3-MBT is being produced in sun-exposed worts at *some* level. And no matter what amounts are being produced initially, they are reduced (driven off by boil, adsorbed by trub, scrubbed out by ferment) to below detectable levels by the time the beer is finished. Possibly all academic, but a meaningful implication might be that that sun-exposure during the boil could reduce the final IBUs…

            • I think I may have learned this over at Chop & Brew, but apparently there’s a pretty big variance in IBU content in a finished beer and one’s ability to perceive differences in bitterness. IIRC, the discussion was centered around using homegrown hops with unknown AA content and formulating recipes. The consensus was that with a little knowledge of the AA content of the corresponding commercial cultivar, you can still use homegrown hops for bittering charges. The beer would essentially be the same, regardless if it had, say, and I’m spitballing here, 50-60 measured IBU’s in it. In the spirit of “academic discourse,” which from experience is just a series oneupmanships, I really wish I had a reference for this. So, I kind of chuckle now when I see some breweries list IBU’s to the tenths place. That’s probably a calculated number for the smaller breweries because I don’t think they have the scratch for an in-house HPLC.

              But, more to the point: If you believe this, and I’m not sure that I’m totally convinced yet, then an IBU reduction by siphoning off isoAA’s via photochemical degradation is likely negligible.

            • Agree DK that any IBU reductions would be minimal and that those variations would not be noticeable.

              And as an aside, Stan Hieronymus’ recent book on Hops makes a similar point as yours regarding how absurd it is to even put IBUs on craft brews as they’re rarely/never actually measuring them. They (like us) ball park the IBU level with a formula and then that’s it. So long as a beer is not severely under-bittered for a style, you’re going to be good-to-go.

    • Ha! Yes, probably. I really want to be down with metric, and I can wrap my head around hops in grams because of the typical dose sizes, but grain weight in kilos and kettle/fermentor volumes in liters still requires too much mental translation.

      • Haha, well I live in a country that uses metric so I feel the complete opposite. Gallons, cups, shoes, hats and whatever it is you guys use is strange to me;-) i have just started to get my head around g/l when hopping so g/gallon is just… Well its not helping i can tell you that. 🙂

  3. Dawson,
    Can you provide any tips on maintaining mash temp in a direct fired tun? I’ve noticed your mash tun is always pretty full and I would assume that helps but recently I switched to a keggle from a cooler (5 gallon brews) and I am always fighting to keep it somewhat constant.

    • Hey Landon (also replying to Doug and Cam here) –

      I typically dough in with about 1.3 qts/lb of grist and it’ll hold a temp quite steady; in cold weather, I do have to supplement with low heat & stir as needed. On this particular brew day, the air temp was in the 40s during the mash, so I did have to goose it with heat once towards the end of the sacch’ rest.

      The Polarware kettles (at least those of the generation that I have) are deep-drawn stainless, so they’re quite thick-walled and heavy, which helps hold the temp. The thermal mass of the mash itself gives some insulation, so as you noted, full is good; and as Alec notes further down in this thread, the surface/volume ratios play a role too (the h:w ratio of my MLT is pretty close to 1:1).

    • I’m also curious about this… I’m mashing in a cooler but my goal for 2014 is to move to a 3 kettle system. How do you hold those temps?!?

      • Some of the old brewing TV shots lead some insight into this. He has the flame going VERY low while he stirs it up. not sure which one he gave the info in, but it’s there somewhere in the millions of episodes. hope that helps!

  4. It’s also possible the higher pH and sugar concentration decreases the chances of the radical finding the sulfur compound, while any that do would volatilize off before chilling. I do ten gallon batches using a similar mash tun and find I lose less than two degrees F even in winter, the key is the lower surface area to volume ratio that a big, squat (as apposed to a narrow keggle), mash provides. Throwing a heavy towel or blanket over the lid keeps heat loss to less than a degree usually.

    • Excellent points, thanks Alec! My own anecdotal experience (and others who brew outdoors) seems to suggest that there’s some factor, or combination of factors, that limits isohumulone shearing during the boil.

  5. MD, what do you think of dropping the C60 and replacing with C40? Sometimes I’m not a fan of the “hit you in the face” caramel attack that is C60. Would 40 offer different taste notes? Would you need to bump up the C40 if you used it to replace?

    • IIRC, the original recipe called for C40 and would make the finished beer a good degree or so of SRM paler – I thought I had some on hand, actually didn’t, and so subbed C60. I hear what you’re saying about the caramel attack, but at 3% it doesn’t seem too pronounced and made for a nice bronze-ish gold color.

  6. Hi Dawson,

    As always your blogpost made for some nice reading. I’m happy to see you trying out the 1217 Westcoast-IPA strain. Bought myself a package last week and am curious to find out how this strain will do in a series of brews (APA, IPA and maybe an DIPA). Im very much looking forward to your tasting notes.

    All the best!

    De Bebaarde Brouwer

    • Cheers, De Bebaarde Brouwer! I just pulled the yeast from this batch for use in an upcoming DIPA as well. I’d love to hear how it works in your batches.

      • Today I’m brewing an American Brown Ale with the old familiar 1272, but will be brewing with this new yeast any time soon.

        I’ll be sure to keep you posted!

          • Today it is brewday! I’ve copied your malt bill, so the only thing that’s different is the hops. Initially the plan was to do a duo-hop with Columbus/Centential, cause I like the Jack Hammer from Brewdog so much. But unfortunaty I only discoverd today that I’m almost out of Columbus.

            Therefore I had to replace most of the columbus with Magnum. Did use some Columbus for FWH and a late edition @ 5′. Loads of Centenial editions (10′, 5′, 3′ and Flame-Out + Dry-hop).

            Could you tell me what % of attenuation you got on your IPA?

            • That’s pretty nice,

              I brewed an Simcoe APA first, and I’m going to drop this IPA on the yeastcake. Probably will mean that I’ll overpitch a little, but I don’t think that will cause any trouble.

              I racked the APA to secondary. It attenuated to a little under 76% (1.045 – 1.011). I guess it will drop a few more points. The sample tasted really nice!

            • Today I racked my Big Beard Double IPA to secondary. It ended up at 81% (1.085 -> 1.016). This is gonna be a one hell of a BIG DIPA! 9% ABV and a IBU of 95. Tasted a bit of the sample, enough to ascertain that is truly was brutally bitter 🙂

              The IPA that I brewed before this DIPA got kegged yesterday and ended up with 71.4 attenuation (1.070 -> 1.020) what was a bit lesser than expected. Stil pretty bitter with 75 IBU, but way more balanced due to the residual sweetness.

              Quite a big difference in attenuation don’t you think?

            • Yes, it is … possibly due to larger population of yeast in the second batch? Or something else – mash temp, sugar, crystal malt? AA% on the batches I’ve done has been consistently in the high 70s. In any case, congrats on the big DIPA – more is more, as they say!

  7. Question sir!
    I’m holding off on brewing anything until my kid (due tomorrow) comes out and the wife and i are completely set with baby stuff and taking care of it. so a number of weeks away. so i have time to plan a few brews… one i haven’t done in awhile is an IPA. I’ve noticed with some of your recipes, you don’t do the usual home brew recipes of “60, 15,10,5,0” etc. You make it way more simple. Is that just personal preference? or is there usually no sense in adding hops every 5 minutes toward the end?

    • Hey Noah,

      First – congrats and good luck on the impending arrival and happy occasion.

      Re: addition times – in the specific instance of this batch, those additions (beginning of boil, 30′ before end, and end of boil) were from the base recipe in IPA.

      Generally, I think appropriate addition times depend on beer style or target parameters, the hops themselves, other ingredients, one’s equipment, and what one envisions for the final product … I don’t think there’s one single all-purpose approach. As Hieronymous writes in Hops: “The rules governing boil additions are about as well understood as those of a knife fight” (may be paraphrased a bit, but that’s the gist).

  8. From the title of the post I thought this was going to be about brewing with acorns. I heard rumor at some point of some of the first settlers in America used them to brew with until they could harvest some cereal grains. I don’t know if its true, but I have seen a brew done with sunflower seeds as part of the mash, so it seems like it would work. I’ve never looked into it, but I’ve always kept an ear to the ground on the subject and haven’t turned up much.
    – Dennis, Life Fermented Blog

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