Appearance: Pours a toffee-like amber color with some slight haze. Even after some time (it has been two months in the keg), the dry-hops impart a polyphenol haze to the brew. Rocky 2-inch head that sticks around.

Smell: Herbaceous hop character assaults the nose with notes of pepper, mint, and chamomile. The Tettnang hopping makes its presence known and masks any sort malt and yeast character.

Taste: Follows the nose with a noble-hop type flavor. The hop character is resinous, earthy and spicy. Subtle one dimensional malt character, and a very clean ester profile coming from the yeast. Some mineral-like flavors round out the taste (interplay between hops and malt?). Average carbonation, dry, and medium mouthfeel.

Overall: I like it, but a weird beer for sure. Not exactly an altbier since the hopping was off the scale for this brew. The malt character was muted for me, but this could be due to the extract that I chose. However, the beer was very satisfying and thirst-quenching despite the aggressive hop profile. Next time I’ll lower the amount of hops and go all grain with a 50/50 mix of Vienna and Pilsen malt.

From these small and almost forgotten beginnings the American craft brewing movement has revived the style. There is a wide range of interpreting saison, with some being sour and quite funky, while other breweries make a beer that is very dry, mineral-like, and earthy. All great saisons have fruity esters produced from characterful Belgian yeast. My most favorite saison to date is Southamptons Peconic County Reserve Ale. This beer was brewed and aged in Chardonnay barrels before being bottle conditioned. Saison-Brett from Boulevard brewing Company is another fond memory. Although I have not had any, I have heard Hill Farmstead makes amazing saisons, Juicy and Ann are particular standouts. Brooklyn’s Sorachi Ace and Saison Dupont are benchmark examples that can be easily found on store shelves.

I have made only one other saison – Petite Spelt Saison. I never wrote a review for this beer as it was being consumed during my move. The beer went very quick to great reviews, and I’ve been missing something like this ever since. This time around I decided to ferment the beer with WLP 670, American Farmhouse blend. I wanted to make something that could store over a long period of time and slowly become sour/funky as this mix has Brettanomyces. Staying with tradition, I bottle conditioned the beer in champagne bottles.

Recipe (6 gallons):

• 10 lbs of floor-malted Pilsner Malt (Weyermann)
• 4 lbs of Flaked Wheat
• 1 lb of flaked Rye
• 8 oz Carared (20 SRM)
• 4 oz of Special B (180 SRM).

Mashed in at 122°F with 1.4 qts of water per pound of grain and held for ten minutes. Raised the temperature to 154°F and held this saccharification rest for 45 minutes. Mashed out at 168°F for ten mintues. Batch sparged and collected 9.3 gallons of 1.055 wort. Boiled for one hour:

• 1.75 oz of Sterling (7.0% AA) at 60 minutes.
• Yeast nutrient and whirlfloc at 15 minutes.
• 2 oz of Sorachi Ace (12% AA) at 0 minutes.

Cooled wort to 68F, aerated for 1 minute with pure O2 and pitched a one liter starter of WLP 670.

Victuals:

• OG: 1.050 (some wort was used for an experiment)
• FG: 1.010
• IBUs: 28.6 (Tinseth)
• ABV: 5.2%

Notes:

2/3/13: BREWDAY. Mashed in perfectly at 122F. Brought to 154F in 8 minutes. Holding at this temp in dead winter proved to be a challenge. Averaged at 154F, but temps swung from 148F to 158F. I’m unable to fine tune heat with the blichmann burner. First runnings: 1.094!! Second runnings: 1.037. Collected 9.2 gallons of 1.055 wort with a mash efficiency of 83%. After boiling, I added an extra gallon of distilled water to get a higher volume.

2/4/13: Pitched in the morning and by the evening there was vigorous activity.

2/6/13: Fermentation temps have been held steady at 69F throughout the most vigorous fermentation. After three days, krausen is starting to subside.

3/2/13: After one month in primary, the farmhouse ale is corked and caged under 2.6 volumes of CO2.

4/20/13: Had several chances to try this beer and I love it. Looking forward to seeing it change over time. Soft wheat dominates the pilsner malt. Lots in the way of fruity esters – peach, apricot, stone fruit. Some funk and a very slight sourness – barely detectable. Spritzy carbonation and thirst quenching. I will lay this beer down for months to come.

An altbier is historically a German ale of copper brown color, close to 4.5% ABV, clean in flavor but a with malty taste. The bitterness is firm  to hold the malt in check, and the head is a tall crown of foam. The word “Alt”, which means old in German, denotes a brew of old heritage coming from Rhineland, while modern altbiers originated in Dusseldorf in the 1800s.

What makes an altbier unique is it is one of the few ales that are fermented cooler than standard ale temperature at 55°C to 64°C. Under these conditions, ale yeast produce very little in the way of esters (more about esters in my last post) and off flavors. Moreover, they are aged in lagering tanks close to freezing. The result is a mellow and clean tasting beer that highlights malt and hops. Traditional ingredients for an altbier are slightly kilned German malts, such as Munich and Vienna malts, and German (noble) hops.

Unfortunately, I’ve only had two commercial examples to draw an accurate comparison for brewing my Alt, Alaskan Amber and Southampton’s Altbier. Both are OK, but nothing to get excited about and I  assume they are a far cry from the original. For my beer, I decided to focus on German hops and I dry hopped with two ounces of whole leaf Tettnang hops. Time was limited for this particular brewday, and instead of a blend of Munich and Vienna, I used dried malt extract. For my yeast, I selected San Francisco Lager (WLP810), which ferments cleanly in the upper 50s.

Recipe (6.0 gallons):

• 7 pounds of extra light DME
• 8.0 oz Caraaroma (150.0 SRM)
• 8.0 oz Carared (20.0 SRM)
• 4.0 oz Special B (180.0 SRM)

Heated 7.51 gallons of distilled water to 150F and added steeping grains for 30 minutes. Removed grains, and rapidly brought to a boil. Added only 1 pound of DME at the beginning of boil and the rest with 10 minutes left.

• 2.0 oz of Tettnang at 60 minutes (pellets, 4.5% AA)
• 0.5 oz of Hallertauer at 60 minutes (pellets, 4.8% AA)
• Whirlfloc and yeast nutrient at 20 minutes
• 1.5 oz of Hallertauer at 0 minutes (pellets, 4.8% AA).
• 2.0 oz of Tettnang (dry hop, whole leaf, continuously in the keg)

Cooled to 62F, aerated for one minute with pure O₂ and pitched a 1 liter starter of WLP810.

Victuals

• OG: 1.046
• FG: 1.012
• ABV: 4.5%
• IBUs: ~34.4 (Tinseth)

Notes:

 1/1/12: Brewday. Pretty straight forward – extract beer. Blichmann burner has been giving me problems in a small gust of wind – the flame blows out. However, found the best setting for maximum boil for Blichmann burner. Had to add back a gallon of water due to a high rate of evaporation. Pitched one liter starter at 62F.

1/2/12: Activity by 12 hours. By 24 hours, beer was throwing blow off. Temp at 61F

1/3/12: High krausen – temps at 62F.

1/4/12: Activity slowing down – 62F

1/6/12: Still some residual activity. Fermentation is lasting longer than I expected – could be due to the strain. Temps have remained at a constant 62F during the whole fermentation.

1/25/13: Racked to keg and carbed to 30 psi. Tastes malty but definite fruity esters are present. Lagering may remove this. Soft water doesn’t seem to be too detrimental. FG: 1.012 and an apparent attenuation of 73%.

2/6/13: Drinking great. Very sessionable. Nice malt flavor, decent head retention and lacing. Beer is still cloudy, mostly due to young age. Very clean ester profile, San fran yeast is a good yeast for pseudo lagers. German hops add quite a unique flavor to this beer – spicy, minty, and herbal. At first I thought the Tettnang dry hop was too grassy, but the flavor is mellowing out nicely.

2/19/13: Drinks very good and is a different flavor. Sessionable and has a unique ester profile.

====

Review of this beer can be found here.

Esters

This remarkable class of molecules is responsible for the fruity aromas and flavors found in fermented beer. Depending on the style of beer, esters play a major role. Top fermenting English ales often have more fruity esters reminiscent of apples, pears, and dark fruit. In contrast, American ales often have less esters allowing for hop flavor to shine. Bavarian wheat beers (Kristallweizen), contain large amounts of isoamyl acetate (banana/clove), while Belgian ales (Saisons) often a have complex mix of esters that make them stand out.

Reacting an organic acid with an alcohol by yeast during fermentation forms these compounds. In the example shown below, methanol is reacting with butyric acid, which smells like vomit, to produce methyl butyrate, which smells like apples or pineapples. I love chemistry.

Enzymes called ester transferases catalyze these reactions within yeast cells that are ultimately secreted from the yeast into wort. The biochemistry behind esters reflects the balance of metabolism inside the yeast at any given moment. Below is a basic diagram of yeast biochemistry during fermentation (Peddie et al., J. Inst. Brew., 1990, Vol 96, pp. 327-331).

Maltose (wort) is transported into yeast cells, converted into pyruvate and acetyl CoA. These two molecules, and acetyl CoA in particular, sit at a biochemical crux inside a yeast cell during fermentation. Any factor (temperature, wort composition, etc…) that affects the amount of acetyl CoA will also affect many other aspects of yeast biochemistry. For the discussion of esters, think of this pathway as a one-way flow. That is, anything that produces more acetyl CoA will eventually produce more esters. For example, with a higher concentration of maltose (high gravity wort) present the more acetyl CoA is produced, which feeds into ester production (hence why barleywines are often fruity).

Acetyl CoA:

The vast majority of esters in beer are produced from yeast during fermentation and are influenced by three things:

1. Wort composition and aeration
2. Yeast strain and health
3. Fermentation conditions

Wort Composition

As I mentioned before, the higher concentration of sugars you have, the more acetyl CoA is produced ending up with an increase in ester production. However, the availability of nitrogen also plays a key role. Higher amounts of nitrogen also pulls this pathway as well, producing more esters in addition to amino acids that are required for cell growth. In contrast, wort that is low in nitrogen slows the pathway and produces less esters. This can be seen in brews that use a high percentage of nitrogen-lacking adjuncts, such as light lagers. It is no coincidence that mass market macro lagers or extremely clean and neutral in taste.

Aeration

The presence of oxygen at the beginning of fermentation is absolutely required for yeast to produce unsaturated fatty acids (UFA) and have healthy cell walls. Acetyl CoA is required for this process and therefore any oxygen will draw acetyl CoA away from ester synthesis to UFA synthesis. In contrast, not enough aeration causes a buildup of acetyl CoA and ester formation. There is also some anecdotal evidence that oxygen increases the expression of some ester producing enzymes, although there is some controversy whether this is actually true.

Yeast Strain and Health

Yeast strain is probably the biggest factor of ester production during fermentation. Genetically, certain yeast strains are designed to turn on ester producing genes that can contribute to fruity overtones. English ale strains fall within this category. American ale strains, on the other hand, have a less capacity to produce esters. Lager yeast even less so. Some strains have been cultivated to produce one specific ester, such as hefeweizen yeast ability to produce banana and clove esters.

Although yeast strains vary in their ability to make esters, all yeast will produce a lot if they are stressed, including lagers. Yeast health is absolutely paramount to avoiding strange fruity flavors in your beer. Pitching an adequate amount of fresh yeast that has been plenty of glycogen levels and oxygen is critical in avoiding unwanted off-flavors. Pitching rates also have a minor influence on esters. That is, lower pitching rates increase ester formation, while high pitching rates tend to produce less. With my experiments I have found this to be highly dependent on yeast strain.

Fermentation Conditions

The state of beer fermentation has a large impact on ester production with temperature being the biggest factor. High temperature increases metabolic activity that in turn increases acetyl CoA production as described in above. The most critical time point to controlling fermentation temperature is about 1-3 days after pitching. Allowing a fermentation to go out of a specific temperature range is a definite way to get more esters. In a previous experiment looking at different fermentation temperatures, Wyeast 1388 produced more esters compared to lower temps. By reducing fermentation temperatures one can dramatically lower the fruitiness found in beer. Although not a concern for the vast majority of homebrewers, fermentation vessels can have a big impact on ester production. Tall, narrow vessels that produce lots of pressure will cause lower esters in the resulting beer.

In summary, there are many factors that can influence ester formation and I’ve summarized it here:

Can the Homebrewer Control Ester Production?

Short answer: yes. However, a dose of common sense is needed if you are concerned about esters in your beer. Do NOT skip oxygenating your wort just because this will increase ester production. You will have many other problems to worry about besides esters in this situation. Don’t avoid high gravity beers because you hate the over ripe fruit that comes along with it. If you want your English Bitter to have an awesome fruity bouquet, do not under-pitch to the point that fermentation starts three days post-pitch. Changing the dial on esters is more of a subtle affair and I’ll list what we as homebrewers can practically do to control it (in order of importance):

1.  Choose the right yeast strain. The most important factor in changing ester profile. Use yeast genetics to your advantage and if you want a clean English IPA, use an American ale yeast paired with British malts and hops. If you want to brew a fruity “east coast” IPA, an English ale yeast may be your cup of tea.
2. Fermentation temperature. Controlling temperature during fermentation is a great way to rein in those esters. However, if you heart is dear to American ale yeast for your IPAs, but you want some extra fruitiness, don’t be afraid to go beyond the manufacturers suggested temperature range. Likewise, if you want “lager-like” character from Wyeast 1056, don’t be afraid to ferment below 60F. Remember, increasing metabolism (yeast growth) drives ester production
3. Pitching rates. This last option is really a distant third to the ones above. The reason I say this is because drastically changing pitching rates can have other effects on your beer and stress the yeast in different ways. Having said that, minor changes can have a positive change to ester production (or inhibition). An English ale that gets a slightly lower pitch rate (0.5 million cells/ml of wort/degree Plato, for example) will slightly bump esters. The same holds true for overpitching.

I hope this primer on esters is somewhat beneficial. Keep in mind that controlling esters is somewhat of a balancing act and interconnected with other molecular compounds found in beer. In next lecture series I will write about fusel alcohols, how they relate to esters, and how you as a homebrewer can reduce or increase them.

This year I submitted three beers, and I’m happy to report that my Mad Hatter Barleywine took first place in the English Barleywine category! This beer is about a year and a half old allowing for the 11.5% ABV content to mellow into a nice warming afterglow. My first review of the beer is here, and I still stand by my feeling that the beer is a tad full in body and under-attenuated. Although rich and complex in malt profile, it comes across syrupy for my taste. Although the beer won first in category, when it advanced to the “Best of Show” round it was eliminated for precisely this reason (they live recorded the judging). Some comments:

• “Big bodied beer with caramel sweetness, dried fruits. Malt sweetness is balanced by hop bitterness. Has definite alcohol warmth.”
• “A malty barleywine with enough with enough hop bitterness to offset malts. Some sherry, and a little hot”.

Score: 37

I also submitted two other beers, Kim’s Berliner Weisse and my American IPA #5. The Berliner Weisse scored the highest I’ve ever received at 44 but did not place. The IPA, scored in the “very good” category with a respectable 34. Honestly, I thought the Berliner would score less as the lactic sourness was not that strong. The IPA suffered from a weak aroma and didn’t have a chance with 60 other entries. Some overall impression comments:

Berliner Weisse:

• “Nice tart aroma, with hints of Brett in the nose. Very distinct and upfront lactic sourness. Very well made beer – almost perfect. Maybe just lacking the “intangible magic” in the finish. Super drinkable and refreshing. Great job”
• “This is a great example of the style. Slight tartness yet super drinkable. Could stand to be even a touch more tart. I’m sure it will age well!”

IPA:

• “A solid well-rounded IPA. Perhaps could use a bit more “style hop” character, but otherwise a very well made beer. I enjoyed it, thanks for sharing!”
• “Nice overall, could have benefit from additional late hops to step up the aroma.”

The American IPA style is so ubiquitous in American craft beer culture, most likely a result of market competition and demands from the consumer. There are plenty of samples to choose from to refine one’s palate and the range within the style can vary considerably. Malt character, body, hop varietals, and yeast are variables used to make this beer and my personal taste gravitates me towards a narrow range within the style. I like IPAs that are very bitter but not harsh and still retain hop aroma and flavor – a difficult feat to achieve in my opinion. For me the beer needs to be bone dry yet balanced to accentuate hop character. Yeast health and fermentation conditions remain paramount to achieve a high level of attenuation. My favorites? Only a few:

• Masala Mama IPA from Minneapolis Town Hall Brewery. A growler of this beer came to me as an extra in a BA trade. My favorite IPA and dream of trying it again.
• Susan from Hill Farmstead Brewery. Tried this beer only once on tap in NYC. Perfect balance of malt and hops.
• Sculpin IPA from Ballast Point Brewing Company. One of the more readily available IPAs, it needs to be consumed fresh to achieve its full effect of hop goodness.

My fifth attempt at brewing an IPA and the description of the beer can be found here. It reflects a winding road of trying to figure out how to make the perfect IPA (for my tastes). This may take a long time, but I feel as is if I came one step closer.

Appearance: Pours a golden orange color and is a bit hazy from the continuous dry hopping in the keg. Massive fluffy white head that sticks around for a long time and leaves laces down the side of the glass.

Smell: Decent floral and citrus aroma. Mango, pine, and passion fruit come to mind. However, with two ounces of whole leaf dry hops and large amounts of late hop additions, I was expecting more. Unfortunately, the aroma does not jump out of the glass.

Taste: Clean and assertive bitterness that lingers in the finish and complements a bready malt backbone. Interplay between the munich and pale malt provides a biscuit-like and nutty finish Fruity hop oils leave a lemon-rind like flavor, followed by orange and tropical fruit. Medium body and well carbonated.

Overall: Not a bad IPA, but could be improved. My favorite aspect of the beer is the bitterness. Aggressive and long lasting, the bitterness is clean, neutral and not harsh in any respect. Warrior is now my standard bittering hop. Unfortunately, hop aroma was lacking and I feel as if I’ve maxed out on the amount of hop aroma I can put into a beer on my system. A hop rocket or hop back may be in my future. Finishing at 1.014, the beer needs to be drier. Next time I will make enough yeast to overpitch and drive attenuation even higher. Other options include the addition of sugar to dry the beer even further. I sent this beer for competition at NYC’s Homebrew Alley 7 and we’ll see how it performs.

I have very high standards for brewing an American IPA. Partly because this style is so ubiquitous in the American craft beer scene, the huge sample size allows me to determine what I specifically crave:

1. High attenuation. For me the beer needs to be dry with little residual dextrins. Malty, thick IPAs and double IPAs are not for me. Forget the crystal malts.
2. Clean bitterness. Some hop varietals are grating to me and reflects their high cohumulone content, such as Chinook.
3. Clean yeast character. This is an obvious characteristic, but some commercial IPAs brewed with American yeast strains produce fruity esters at higher fermentation temperatures.
4. Fresh dry-hopping. This provides the best flavor and aroma in my opinion.

For all of these requirements and the fact that it is my favorite style, I have trouble brewing this beer. My first attempt at an American IPA came out too harsh. There was an astringent character arising from phenolics or high alcohol. My second attempt was probably my best so far, but the beer lacked in bitterness and resembled more of a pale ale. My third attempt was an IPA that focused on hop-bursting where all hop additions are added towards the end of the boil. I was really disappointed in the lack of hop flavor from this beer. For my fourth IPA, I brewed solely with Simcoe. The beer was good but still needed something extra (perhaps it was one-dimensional?).

I’m often very critical of my work (whether it is brewing or work related) and perhaps my IPAs suffer from this. However, given the high bar that I set for this style, I think I have room for improvement. This next IPA (my fifth) uses a blend of American type hops, with Warrior setting the tone for bitterness. I have heard this hop has a very clean and smooth bitterness. As this is my second batch of beer in Pennsylvania, I will be brewing with local water, which is very hard and high in bicarbonate. Lastly, my unfinished basement stays at a constant 63°F which will keep my fermentation clean.

Recipe (6.5 gallons):

• 8 pounds of Pale malt (2-row)
• 6.5 pounds of Munich malt (9.0 SRM)
• 1 pound of White Wheat malt

Mashed in with 1.4 qts per pound of grain targeting 144°F for 30 minutes. Raised temperature to 156°F for another 30 minutes. Mashout temp reached in 3 minutes (goodbye kitchen stove!!). Vorlaufed as usual and collected about 4 gallons of 1.083 wort. 2nd runnings: 1.045. Collected a total of 6.75 gallons of 1.071 wort, which is still short of my target 7.5 preboil volume. Added 1.2 gallons of water to dilute wort and began boil.

• 1 oz of Warrior at 60 minutes (16.7% AA)
• 1 oz of Falconers Flight at 15 minutes (11.4% AA)
• 1 oz of Cascade at 10 minutes (6.2% AA)
• 1 oz of Cascade at 5 minutes (6.2% AA)
• 1 oz of Simcoe at 5 minutes (13% AA)
• 1 oz of Chinook at flame-out
• 2 oz of Citra at flame-out
• Nutrient and whirlfloc at 15 minutes.

Dry hopping (continuous in the keg):

• 1 oz of Simcoe (whole leaf)
• 1 oz of Amarillo (whole leaf)

Cooled wort to 65°F and aerated with pure O2 for one minute. Pitched 2 liter stepped-starter of San Diego super yeast (WLP090). Other notes:

11/29/12: In morning, the beer was already throwing off blow off. By the time I got home, rubber stopped came clear off carboy and yeast was spewing out. Temp unknown, but assumed to be in mid to low 60°F (Oatmeal cookie ale ambient was 61°F).

12/5/12: Gravity: 1.016. Still going so I decided to bring upstairs on heat vent to raise temps.

12/6/12: Activity increased slightly. Tasted young and very hoppy. Looking forward to trying this.

12/7/12: Hardly any activity so I brought it downstairs into basement.

12/12/12: Went down to 1.014. Final gravity. 6.7% ABV

12/17/12: Racked to keg at 30 psi.

Victuals:

OG: 1.065

FG: 1.014

IBUs: ~78 (Tinseth)

ABV: 6.7%

===

Review can be found here

Appearance: After 7-8 months in the bottle, the spent yeast has all settled to the bottom and out pours a crystal clear beer with the color of light straw. The cork came off with a loud pop, indicative of high carbonation. Large bubbles rise to the top and disappear just as quickly. The head of the beer lasts just about ten seconds but is to be expected due to the high carbonation and acidity.

Smell: Light farmyard funk hits the nose, followed by freshly prepared dough balls. Some cracker and toast peek through, followed by wet hay. Smells great.

Taste: The predominant flavor is freshly baked dough, with a tame acidity. Slight lemon-like tartness that stays in the background. Malts also shine through with cracker, toast, and bread. Esters also a play a supportive role, with notes of pear and pineapple. An aggressive carbonation gives the beer a refreshing zip. Bone dry.

Overall: Disappointed in the lack of acidity. After seven months I would expect the lactobacillus to produce more acidity than this. Perhaps more time in the bottle will improve this. Matt Chan, a friend of mine that has gone on to the professional brewing world, has suggested that you pitch Lactobacillus first, wait for the pH to drop, then add brewers yeast. He pointed me to this information presented from Wyeast, here. This may be something worth looking into. For now, I have a few 750 ml bottles that I plan to tastes over time to see if the beer changes.

While temperatures effects on beer is well-known, I wanted to see for myself and it provided a great teaching point for the yeast class. A Belgian blonde ale was fermented at three different temperatures: 60°F, 72-74°F, and 86°F. I chose to ferment with Wyeast 1388 since this Belgian ale is characterful and has wide suggested fermentation temperature range. Each beer was bottle condition for two weeks and served in the class. Each student was instructed to sample the beer and score what flavors he/she thought was present (no limit to score).

Results:

The results were somewhat predictable, but there was some surprises as well. As expected, the beer fermented at 86°F was the fruitiest beer, although not by much since the strain itself produces fruity beers. The warmer fermented beer had the highest score for being thin/watery and almost everyone noticed the green apple aroma and taste as well. Surprisingly, the lower temperature fermented beer was extremely bitter and was picked up by most people in the yeast class. Phenolics (spicy/band-aid/sharp) and sulfur was also attributed to the beer fermented at 60°F. The control beer, which hit the suggested fermentation temperature range at 72°F – 74°F was the maltier of the three and had slightly more fusel alcohols.

I decided not to measure gravity over time since I did not have the time (I was away for three days in the middle of fermentation). However, the biggest surprise came when I checked the final gravity:

• 60°F: 1.009
• 86°F: 1.006
• 73°F: 1.001

Conclusions and Discussion:

The predictions of high fermentation temperatures held true: the beer had more esters (fruity), was thinner, and had more green apple flavor (indicative of acetaldehyde). With higher temperatures comes higher metabolic activity. More glucose (which originally came from other worts sugars such as sucrose and fructose) is pushed into the glycolytic pathway to produce excess pyruvate. The pyruvate, if not completely used in yeast biochemistry to produce ethanol, will breakdown into acetaldehyde and leak out of the cell (this can sometimes break down to diacetyl as well). More acetyl CoA is also produced which helps with the formation of esters by bonding with an alcohol. The 86°F beer also had a vigorous fermentation, which undoubtedly helped scrub the beer into a thinner form and reduce bitterness. As I bottled the 60°F sample, it was still a hazy from yeast in suspension, indicative of a sluggish fermentation. Surprisingly, this beer was noticeably bitter and had a unique sulfur component to the nose. My running hypothesis is that the fermentation was not vigorous enough to blow off any residual sulfur generated during fermentation. This often occurs with lager yeasts and why lagering needs time and proper attention to temperatures. The control beer was spot on for a clean Belgian pale ale. The slight fusel score may be indicative of strain itself.

On an interesting note was the odd finishing gravities, with the control beer almost completely fermenting out while the other two beers did not. I was expecting to have a lower gravity in the 86°F sample compared to other brews. It’s tough for me to explain this, but my gut feeling is the both the colder and warmer beer are stressed to the point that fermentation stops prematurely. This suggests that the temperature range given by the manufacture holds true as the optimal temperature range. Having said that, the class unanimously agreed that all three beers were good and drinkable. While most people could pick out the higher temperature beer, most students had trouble identifying the control beer from the 60°F (including myself). Similar to using different pitching rates, this suggests that playing around with vastly different fermentation temperatures represents another tool in the brewer’s toolbox. Of course, this statement only holds true if you adhere to healthy yeast and pitching principles.

Future:

Ah… So much to do. Similar to my pitching rate experiment, it would be great to have a panel of different yeast tested at different temperatures. Although interesting, at some point I would be re-inventing the wheel by repeating what major yeast manufacturers have already tested. More interestingly, I would like to see if pitching yeast at different temperatures has any effects. For example, a yeast starter that is cold versus warm. Another idea would be to keep the pitching yeast constant in temperature but vary the wort temperature. Pitching into warm versus cold wort for example. Lastly I would like to point out that these experiments, although interesting, are not very quantitative. Putting some actual metrics on some of these results is something I need to do, but now they reflect small-scale experiments that non-scientific audiences can sink their teeth into. For those interested in serious data analysis in homebrewing experiments, definitely refer to Braukasier’s blog. Some of his experiments are fascinating and he has the statistics to back it up.

Appearance: Pours a crystal clear amber in color with reddish highlights. Coarse carbonation yields a small head that quickly dies to thin wisp. Swirling the glass demonstrates a high degree of viscosity and legs.

Smell: Honey and malts with mashed raisins. Absolutely no hop character to speak of. The malt profile completely dominates the nose with a thick aroma of sticky sweetness.

Taste: Malt bomb. Unfortunately, bitterness is restrained and does not cut into the thick and chewy malt character. Complex malt profile of caramelized figs, cocoa covered raisins, and sharp stone fruit (maybe form yeast?). Mouthfeel is full bodied, thick, and velvety. Coats the tongue. The alcohol, while not completely masked, gives the beer a noticeable warming.

Overall: Given the underattenuation (1.120 to 1.035), I’m a bit disappointed in the beer. Although not bad it misses the mark for me. It’s just too sweet, thick, and overly malty. Next time I will need to pitch more healthy yeast to get better attenuation, or start with a lower original gravity. While I like the approach of malt layering in this beer, it needs to be backed up with higher attenuation. The bitterness also needs to be at least 20 IBUs higher to cut through all the malt.