Technical Notes on Fermentability

Wort fermentability can be a confusing topic. In a simple sense, base malts, toasted specialty malts, and unmalted adjuncts contribute long chains of sugar molecules (i.e., starches). The enzymes contributed by the base malt clip chains of sugar molecules of various lengths from the starches. Shorter chains are fermentable sugars, slightly longer ones are unfermentable dextrins.

The saccharification rest temperature is the simplest variable to adjust to alter the percentage of carbohydrates in the wort that will be short enough for brewer’s yeast to ferment. This is because the enzyme (alpha amylase) that works most effectively at the upper end of the standard 140-160°F range produces both sugars and dextrins, while the enzyme (beta amylase) that works best at the lower end of the range produces maltose, which is easily fermentable by brewer’s yeast. At lower temperatures especially, allowing more time for the beta amylase to work also boosts fermentability (if you only mash for 10 minutes at 142°F, the result will not be a very dry beer). Not much controversy there I hope.

But, what other aspects of the recipe/process influence fermentability? I’m not talking about the fermentation, which is a completely separate, but equally important topic. Today I'm focusing on the carbohydrate profile of the wort. Maybe the water-to-grain ratio of the mash? How about the percentages of various base malts, specialty malts, and unmalted grains? Or a long boil with all that kettle caramelization? Over the last few weeks I bumped into three experiments/studies which address these questions.

The most common secondary factor that I've heard influences fermentability is the water-to-grain ratio of the mash. It is often said that thicker mashes yield less fermentable worts. I’d never paid too much attention to this rule, but it is worth knowing (especially if you are considering switching to thin brew-in-a-bag mashes) that it isn’t accurate. Kai Troester found that: “Contrary to common believe no attenuation difference was seen between a thick mash (2.57 l/kg or 1.21 qt/lb) and a thin mash (5 l/kg or 2.37 qt/lb).” An assertion he also supports with several references to technical brewing texts. His white paper summarizes this, and a number of other interesting experiments he has done on factors influencing fermentability and efficiency as well (e.g., calcium, pH etc.).

Many homebrewers think of crystal/caramel malts as adding only or mostly unfermentable sugars. While this makes sense when steeping them for an extract beer, I’d always wondered how dextrins added to an enzymatic mash would survive when much larger starches contributed by base malts do not. Over on HomeBrewTalk, Nilo posted results from experiments he did showing that crystal malts (especially paler varieties) are not a great way to decrease wort fermentability. Steeping crystal malt alone resulted in a wort that was only 40-50% fermentable with S-04. However, a mash with equal parts of pale 2-row and crystal lowered the fermentability (compared to 100% base malt) by only about 3% for C10, 11% for C40, and 13% for C120 (significantly higher attenuation than would be expected by averaging the attenuation of the tests with crystal and 2-row alone). His results suggest that using a more reasonable 15% crystal malt would only result in a reduction of the attenuation by 1% for C10, 3% for C40, and 4% for C120. Not insignificant, but only an addition of .0005-.002 to the final gravity for a beer that starts at 1.050.

According to another of Kai’s experiments, in the same paper referenced above, lowering the enzymatic content of the mash by using a base malt with a low diastatic power, like dark Munich, can reduce fermentability compared to a paler malt. It may be that some of the difference in Nilo’s crystal malt test could be accounted for by this, making his results even less significant under real world recipe conditions. Kai theorized that a similar affect could be achieved by adding a large percentage of unmalted grain, although it is unclear at exactly what average diastatic power of the grist wort fermentability is reduced, considering he achieved similar results from both Pilsner and Munich malts. This seems to dispute the basis that some brewers have for adding corn or rice to the mash to boost fermentability. While these adjuncts will dilute the malt flavor, they do not have the same effect as adding highly fermentable sugar to the boil. At best the amylase enzymes contributed by the base malt will produce a similar sugar profile from adjunct starches as the starches from the malt itself.

In the final study, Ankita Mishra examined how the fermentability of wort is altered through non-enzymatic processes in the boil (among many other changes to the wort). During the boil sugars and amino acids in the wort interact to produce melanoidins, in a process called the Maillard reactions. According to the study this can significantly, although only slightly, reduce the fermentability of the wort (the difference of extending a 30 minute boil to 120 minute was an increase of only .001 to the FG). This would also suggest that the melanoidins produced by either malting or decoction mashing could reduce fermentability, possibly explaining some of the differences Kai witnessed when mashing dark Munich compared to Pilsner malt. Caramelization happens primarily at much higher temperatures than those achieved during a standard wort boil, especially close to the target pH of 5.0.

You can look at the methods for manipulating fermentabilty either as ways to preserve body and some sweetness in a clean beer, or as ways to preserve carbohydrates for the slower working wild yeast and bacteria in a mixed fermentation. Brettanomyces, Pediococcus, and some strains of Lactobacillus are capable of producing enzymes which break apart carbohydrate chains too long for brewer’s yeast to ferment. My understanding is that melanoidins are not fermentable by any of the microbes found in sour beer, but I’d be interested if anyone knows otherwise!

Hopefully this brief literature review helps when designing a recipe, or altering your process.

Malt Whiskey Barrel Rye Stout Tasting

Barrel aging requires dark arts not taught in most homebrewing books. It adds an additional layer of complexity to the timing and process compared to aging in impermeable fermentors. Last fall, I timed my brew days so that by the time the first beers had extracted enough character from my two 20L Balcones barrels (about three weeks), the second batches were ready to take their places. Being prepared to drain and then refill a barrel on the same day eliminated the risks of leaving it empty, or the hassle of burning a sulfur wick or filling with a holding solution.

The second beer aged in a barrel extracts a softer wood and especially spirit character than the first. The extraction also requires a longer time period. Many breweries age all of their non-sour beers in first use barrels, but Goose Island had great success aging Bourbon County Rare (imperial stout) and then King Henry (English barleywine) in the same set of 23-year old Pappy Van Winkle bourbon barrels. Not the same barrels, but Goose Island has also produced at least one sour beer (Dominique) aged in barrels that previously held the standard Bourbon County Stout. A 10 gallon batch of sour brown in currently split between in my third use barrels.

The first beer I aged in my Texas Single Malt barrel was a rich caramel-focused strong lager. When I judged that it had extracted enough flavor and was ready to lager, I racked it to a keg, and rinsed the barrel three times with near boiling water. My naive assumption was that the heat would be enough to kill any brewer’s yeast that wasn't rinsed out. I was aware that it is nearly impossible to sanitize wood once it is exposed to Brettanomyces, but surely brewer’s yeast couldn't be as hardy!

Valuable lesson learned, about a month after this rye stout was racked into the barrel it blew off the hard bung. New rule, if you want to age two clean beers in the same barrel, use the same yeast strain to ferment both! The resulting beer is still pleasant, but the additional fermentation reduced the sweetness and body below my original target.

Malt Whiskey Barrel Rye Stout

Appearance – Opaque black body with a solid light-tan head. The flaked rye provides wonderfully sticky retention and lacing.

Smell – Toasted wood, chocolate, plums, slight warm alcohol. The aroma is bold, but it is is still young and a bit brash. All the elements I want in a barrel-aged stout are already here, they just need time to mellow and blend.

Taste – Similar flavors to the nose, bitter chocolate and espresso. The barrel character fills in the gaps with vanilla and toast, not dominating the malt profile. The finish is firmly bitter, split between hops and roasted grains. The lingering character is faint charcoal, almost smoky. Relatively dry for a big stout, but there is enough sweetness to prevent the bitterness from being overwhelming.

Mouthfeel – Even after a few minutes of taking photos, the carbonation is still higher than I wanted. Luckily the residual lager yeast in the barrel kicked in mostly before bottling, so carbonation is just slightly higher than I intended. The Rumble Barrel Aged Imperial Porter wasn’t so lucky. The beta glucans contributed by the rye do an admirable job suggesting a bigger body without the sweetness you’d expect from it.

Drinkability & Notes – Drinks like a stronger beer than its 1.080 OG suggests. Classic imperial stout character without the syrupy sweetness. The barrel adds a wonderful layer of complexity that is much more intriguing than I've been able to achieve with oak cubes. I'm excited to see how this one ages over the next year!

Cabernet Grape Lambic Tasting

Some batches of sour beer take a little longer than I originally plan. The beer I’m drinking tonight was brewed in June, 2009. The majority of the base lambic was bottled, with delicious results, about a year and a half later. This portion was racked into two one gallon jugs with a total of two pounds of Cabernet sauvignon grapes. The flavor was never spectacular, so I was never motivated to do anything with it. Eventually (i.e., two years later) a sample I pulled convinced me to finally get around to bottling.

Cabernet Lambic III

Appearance – The color is between rosé and a brand new penny. Crystal clear. Not nearly the saturated garnet of the batch Nathan and I aged on the same wine grapes with double the ratio of fruit to beer. The tight white head stays aloft for a few minutes before dissipating completely.

Smell – Nuanced funky nose. I get lemon peel, minerals, with some raw-barnyard Brett. The grapes add a deep subtle fruitiness, but it really isn’t identifiably vinous. No detectable off-flavors from the advanced age, Brettanomyces is a superb anti-oxidant!

Taste – Bright lactic-acidity, a severe case of the funks, and vanilla-oak through the finish. The Brett character is not to the level of being objectionable, but it obscures some of the more enticing fruit flavors. As my palate becomes desensitized to the initial wave, I detect more citrus zest, and faint jammy grapes. Many of the elements of a great sour beer are there, but the pieces don't fit together perfectly.

Mouthfeel – Medium-high carbonation on top of a thin body. Not tannic or otherwise rough or overly dry. I had one bottle gush a couple months ago, but the rest have been fine so far.

Drinkability & Notes – Not my finest work, but the effort of my first turbid mash (and pitching bottle dregs from a 3 Fonteinen Oude Gueuze) really made this batch more lambic-like than either of my previous efforts. The grapes needed to be more aggressive to make a worthwhile contribution to the flavor, but the fermentation sparked by their sugars did boost the acidity closer to where I wanted it compared to the straight version.

Rum Barrel Aged Quad Tasting

This "American" quad was the first of the four clean barrel-aged beers I brewed during September and October 2012. It spent three weeks in a 5 gallon (20L actually) American oak barrel that previously held Balcones Rumble ("Made from the finest local wildflower honey, mission figs, turbinado sugar and natural Texas Hill Country spring water."). The pairing of those flavors with the caramelized dark fruitiness of a strong Belgian style beer was too obvious to pass over.

Rumble Barrel Quad

Appearance – Darker than a standard quad, downright porter-esque. The D-180 candi syrup added more color than I expected, I could easily drop the .6% Carafa Special II from a rebrew. The dense tan head displays terrific retention.

Smell – Lots going on in the nose. Dark and dried fruits especially, but some brighter banana bread notes too. There are lightly boozy barrel-character supporting the aromas of the candi syrup and dark caramel malt. As it warms rum-varietal alcohol emerges and the nose takes a savory turn, ever so faint tomato paste.

Taste – The flavor leads with sweet caramel, toasted grain, raisins, and figs. Despite the color, it doesn’t taste like a Belgian interpretation of a porter or stout. The oak lends vanilla, light coconut, and damp wood to the finish. Amazing what the beer picked up in just three weeks of barrel-aging. The alcohol is still slightly hot, it’ll benefit from at least another six months in the bottle.

Mouthfeel – Solid mildly prickly carbonation buoys the slightly sticky body. Slight tannins from the oak prevent the stickiness from being cloying. Feels substantial compared to many native Belgian beers.

Drinkability & Notes – Certainly not a session beer, but the sweetness does a good job balancing the barrel character. This is one of those strong beers that is “worth” the high alcohol, there are no 5% ABV beers that taste like this. I wish I’d brewed enough of the base beer to bottle a six-pack without time spent in the barrel to compare. The match is almost too good, making it hard to determine where the various flavors originate. Thanks again to Balcones for sending the Rumble barrel to me. They’ve got a variety of beers (including this one) on the way to them as I type!

Craft Beer Bottle Sizes (Revisited)

A couple years ago I posted a short rant about the prices that many craft breweries charge for large format beer bottles (i.e., bombers and 750 ml). A few weeks ago Clay Risen contacted me to ask if I would talk to him for an article he was writing on a similar subject for the New York Times. After the article was published last week, I witnessed heated debate on message boards, Facebook, email, and in person from my friends. I heard a lot of interesting opinions both in support of and against the case presented in the article. Granted I was only quoted, so the negative comments didn't cut too deep.

The issue I had with a lot of the complaints was that they missed, what to me, is the main point: I see no benefit to the consumer that compensates them for the higher per-ounce price of larger bottles of the same beer. I understand some of the reasons that breweries choose to package their most interesting/expensive beers in larger format bottles, but that doesn't mean that it is a positive thing for me as a beer drinker! Don't think I'm blaming just the breweries here though, craft beer drinkers are just as much to blame for being willing to pay an inflated price ounce-for-ounce for the identical beer sold in larger bottles!

I have learned that in other parts of America it is less common for stores to allow "make your own six-pack" or similar deals to buy individual 12 oz bottles of any of the beers they have available. As a result, in some areas people might prefer a bomber for the lower total cost compared to a six-pack for sampling a new beer. However, this is still a sub-optimal situation from my point of view. I also worry about alcoholism masquerading as craft beer appreciation, just because I am physically capable of drinking 3/4 of a liter of 13% ABV Imperial Stout over the course of an evening (containing more alcohol than in a six-pack of Bud Light), doesn't mean it is a good idea!

The person who seemed most personally insulted by the article was Garrett Oliver of Brooklyn Brewing. On Thursday he took to the Brewers Association Forum to post the message below. I thought he deserved a rebuttal, so I sent him the email that follows (to which I have not yet received a reply). If you haven't already, read Clay's article, and the chatter, and let me know what you think!

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Dear Forum,

Yesterday The New York Times published an article "Craft Beer's Larger Aspirations Cause A Stir". You can see it here: http://www.nytimes.com/2013/03/06/dining/craft-beers-trend-toward-larger-bottles-causes-a-stir.html?ref=dining&_r=0.
In this article, The New York Times, usually a fount of very good beer writing, essentially posits that craft beer producers - meaning many of us - are money-grubbing elitists trying to drag humble beer away from its populist roots. The writer says that 22 oz. and 750 ml bottles are "getting a chilly reception from many drinkers" and that "many beer drinkers are uncomfortable with the notion of drinking beer like wine, to be split among several people." Here's another quote for you:

"The trend toward large bottles is part of what is being called the "wine-ification" of beer, the push by many brewers to make their product as respectable to pair with braised short ribs as is a nice Chateauneuf-du-Pape, and at a price to match."

Let me be clear. I love The New York Times - half the internet would disappear tomorrow if it ceased to exist. But this article is so replete with omissions and chock-full of inaccuracies that I feel we cannot give it a pass. It is know-nothing opinion masquerading as reporting. Anybody here heard from customer saying that they don't want more big bottles of interesting barrel-aged beers? No, me either. We can't even keep up, and I'll bet you can't either.

Aside from this, wine itself is not "wine-ified". About ninety percent of the American wine market is bag-in-box or jug wine in a big bottle with a finger loop. This is the "true" American wine market, which looks exactly like the beer market - 10% at the top, and 90% at the bottom. And it was always so. Museums in Europe are filled with ornate gold and silver beer vessels, and beer has always been on the tables of kings and peasants alike - just like wine. The large bottle with the mushroom cork is original to beer, not to wine. So why is the "paper of record" telling us what beer ought to be? And our traditions and history? And what our customers are asking us for? It seems that the writer wants us back at the kid's table. And keep in mind that many, many other papers copy what the NYT does.

I don't know about you, but I'm very, very tired of this. If you think I dost protest too much, I suggest you think again. The NYT is massively influential, it's read world-wide, and this article will be read by many more people, I suspect, than reads the entirety of the dedicated beer press.

To their credit, when I complained to an editor, the NYT decided to open the online article for comments. As of this hour, there are 42. I want to see 400. Please let them hear from the rest of you. Comments and "top emailed" is how they keep score. Tell them the truth. Tell them what you've seen out there, what you're here to do, and what your customers are telling you. We need to send this sort of "journalism" packing. Please go to the Times website and weigh in.

Cheers,
Garrett Oliver, Brewmaster
The Brooklyn Brewery
Editor-in-Chief, The Oxford Companion to Beer
Brooklyn, New York
www.brooklynbrewery.com
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Mr. Oliver,

As the homebrewer (blogger, author, brewing consultant etc.) quoted in the recent NY Times article, I thought I’d offer you my perspective. I certainly don’t agree with everything Clay wrote, but I think the overarching issue of larger format beer pricing is a valid one.

A couple years ago I crunched the numbers at a local store here in DC, and for craft beers bombers were generally a 25-50% mark-up per ounce over single 12 oz bottles of the identical beer. That relationship is inverted for macro-bottles, with the larger formats discounted by the ounce. As a beer consumer, I always opt for smaller bottle when given the choice. Even if I was planning to share the beer, why not open two small bottles rather than one larger? Many beer drinkers are victims of price anchoring. Not realizing that a “reasonable” $10 750 is more expensive than a $28 six-pack.

I understand that big bottles can be beautiful, and raise the perception of beer, but packaging stronger beers in them creates problems. I’ve got a 2+ year old bottle of Black Ops in my basement, still waiting for the day when I have the right group of people over to enjoy it. On the other hand I’ve got a case of Bell’s Expedition that I’ve been drinking through a few bottles a year, watching it change. Something I could never do with a beer only available in large bottles.

Unlike a bottle of wine, beer will go flat after opening, making it less than ideal for drinking over multiple nights. Beer also has the sediment issue, the last pour from a large bottle is pretty murky after being passed around a table of 7-8 people at a tasting. Of course I still buy big bottles of barrel-aged beer and other fun stuff, but only because that is often the only choice breweries present me with. It is inspiring to drink beers created with daring and unique flavor combinations. However, I feel like some brewers (clearly not you) release beers based on a good idea that still needs refinement, packaging what is essentially a glorified test batch in a large bottle to extract the maximum amount of money for someone who “needs” to try it once.

Cheers, and thanks for everything you’ve done for beer and brewing!

Michael Tonsmeire

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The irony of this whole situation is that there is a high likelihood that Modern Times will be selling large bottles of our limited release beers. We'd originally planned to package 12 oz bottles of the beers from the barrel program, but as a result of a protest from the local police on the local licensing, we won't be able to sell smaller format bottles out of the tasting room. How forcing people to buy larger bottles of barrel-aged sour beer is in the public interest, I have no idea! Luckily after a year we'll be able to apply to have this restriction lifted, assuming we've been well behaved.

Hibiscus/Galaxy Wit Recipe

Belgian wit is a tricky style to nail, at least judging from most of the renditions I've drank. The soaring balance of spices, yeast character, and wheat often falls when one element (usually the spices) dominates. Common issues include pithy dried orange peel bitterness, hot-dog flavored coriander, and a flabby/bland base beer. My favorite example is St. Bernardus Witbier, with its subtle tartness, gentle spicing, and balanced yeast character. If I could brew a wit that good, I’d be satisfied!

I hadn’t brewed a wit since my first year as a homebrewer. That batch, based on a recipe from Radical Brewing, called for a cereal mash. That won’t be an option on Modern Times' 30 bbl brewhouse, so we opted for an infusion mash with a combination of flaked and malted wheat, and a touch of oats. After cooling a sample of the mash to room temperature and using my meter to measure the pH at 5.8, slightly above the ideal range, I added .25 lbs of acid malt. I also acidified the sparge water with a teaspoon of phosphoric acid. This is a beer where my goal isn't to impart sourness, but the correct pH will result in a crisp and refreshing balance.

For spicing I went with coriander from an Indian grocery store. This variety is much more citrusy/fruity than the variety carried on most supermarket spice aisles, which is often reminiscent of celery, ham, or hot dogs. Indian markets also carry spices for a fraction of the cost of supermarkets and specialty spice shops. For orange I went with fresh Temple oranges (actually a tangor, tangerine-orange hybrid). I harvested the zest with a rasp/Microplane grater to minimize the amount of bitter pith collected.

I added both the coffee-grinder-crushed coriander and zest at the end of the boil. I find that late boil spice additions do not have the bright punch of post-fermentation spicing, but their character becomes more integrated as the enzymes from the yeast work to change the character of the spices. If I was brewing a straight-ahead wit, I would have added a small amount of chamomile as well, as its juicy-fruit aromatics worked so well in the Radical Brewing recipe.

That first batch of wit was fermented with WLP400 Belgian Wit Ale Yeast, until it stalled around 1.020. I was new to brewing, and with the ABV within the suggested 3.6-4.2% ABV range (like many recipes in the book, oddly low considering the 1.052 OG), so I bottled. A few weeks later the first one blew. When I mentioned what happened to Mike Roy, who was letting me help out at Milly's Tavern in Manchester, NH for a few days, he told me that he'd stopped using the strain after experieincing a similar stall (Mike is now the brewer at Franklin's in Hyattsville, the closest brewpub to my house).

For this batch, I had a fresh yeast cake of Wyeast 3711 French Saison from my second batch of Lomaland. It is fruitier than many saison strains, and at a moderate fermentation temperature I hoped it would be clean enough not to overwhelm the spices. WY3711 presents an opposite issue to WLP400, its high attenuation rate necessitated a hot saccharification rest to preserve any dextrins. Despite mashing at 158F the yeast still achieved 82% AA.

Now for the twist. This ten gallon batch was split three ways. I'll bottle a six-pack plain for comparison, with the rest receiving a second round of flavoring. Half was dry hopped with Galaxy. It is a hop I’ve had less than terrific luck with in DIPAs, but hopefully 2 oz of pellets dry hopped will enhance the fruity character and balance. I'll dose the other keg with a hibiscus “tea” extraction. This will add a bright pink color, light tartness, and fruity-cranberry aromatics. For more information on this process see what I did for my tart-floral-gruit.

Hibiscus-Galaxy Wit

Recipe Specifics
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Batch Size (Gal): 10.50
Total Grain (Lbs): 19.25
Anticipated OG: 1.049
Anticipated SRM: 3.5
Anticipated IBU: 15.2
Brewhouse Efficiency: 75 %
Wort Boil Time: 75 Minutes

Grain
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41.6% - 8.00 lbs. CMC Superior 2-row
31.2% - 6.00 lbs. Flaked Wheat
20.8% - 4.00 lbs. German Wheat Malt
5.2% - 1.00 lbs. Quick Oats
1.3% - 0.25 lbs. Acidulated Malt

Hops
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2.50 oz. Hallertau Hersbrucker (Pellet 3.00% AA) @ 60 min.
2.00 oz. Galaxy (Pellet, 12.00% AA) @ Dry Hop

Extras
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0.50 tsp Yeast Nutrient @ 20 Min.
4 Temple Oranges (Tangor) Zested @ 0 min.
0.75 oz Indian Coriander @ 0 min.
Hibiscus Tea @ 0 Days

Yeast
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WYeast 3711 French Saison

Water Profile
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Profile: San Diego

Mash Schedule
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Sacch Rest - 60 min @ 158 F
Sacch II - 15 min @ 163 F

Notes
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 Brewed 2/17/13 by myself

Added three handfuls of rice hulls to the grist.

Adjusted carbon filtered DC tap to San Diego (Baking soda, gypsum, CaCl, Epsom, and kosher salt), no distilled dilution, for the mash and batch sparge. Tried to boost the temperature to mash out, but I'd lost enough temp that it just brought it to 163 F.

Mash pH came in slightly high at 5.8 @ room temp (according to my meter), so I added 4 oz of acid malt to bring it down slightly. Added 1 tsp of phosphoric acid to the sparge water.
Collected 10 gallon of 1.049 runnings.

Fresh zest from 4 Temple oranges, Indian coriander.

Chilled to ~65 F, topped off with 1 gallon of distilled water to reach target volume/gravity.

Yeast harvested from Lomaland #2, 2/3 cup of thin/clean slurry pitched into each. Left at 65 F ambient to ferment. Quick start to fermentation, did not warm, allowed to free-rise only.

2/25/13 Down to 1.009 (considering the mash temp, wow!). Dry hopped half with 2 oz of Galaxy pellets, loose. Agitated the wort twice a day for remainder of time in bucket.

3/3/13 Racked the galaxy dry hopped half into a purged keg.

3/17/13 Bottled one gallon plain with .75 oz of table sugar. Kegged the remaining 4 gallons with a tea made from 3 oz of hibiscus mixed with 3 cups of just off-boiling water for 5 minutes.

4/11/13 Galaxy dry hopped portion really brought out the citrus. Finally a beer I brewed with Galaxy that I really enjoy!

5/9/13 Hibiscus portion is rocking! Beautiful color, and a complex and refreshing blend of fruity aromatics. Hard to decide which I enjoy more.