Saturday, September 25, 2010

Troubleshooting Beer

Every home brewer knows that some times a batch of beer will taste a little "off". This is not uncommon and there are ways to determine and fix these issues. I have listed some of the most common problems and how to fix them. By no means is this list comprehensive, I have tried to cover the flavors that can be easily detected and avoided. There is a bit of a recurring theme in off flavors and that is sanitation. Above all to make amazing beer your process must be free from infection and healthy yeast must be used.

In order to fully understand where off flavors come from during the fermentation process you need to understand the chemistry behind the magic. The flow chart to the right from Brew Chem 101 steps through the fermentation process. I would highly recommend getting this book if you are interested in the science behind making truly great beer. The process of fermentation is basically taking carbohydrates and converting them into ethanol by breaking down the sugars. Those are only the two end point though, as you can see the transformation from sugar to alcohol has many steps in between. Some of these stops along the way can actually be the very cause of the undesirable flavor. The first flavor we are going to cover is the last step before ethanol in our chemical reaction, Acetaldehyde.

Flavor: Fresh Cut Green Apples
Cause: (Acetaldehyde, CH3CHO) Green apple flavor is produced during fermentation and is common in beer that is not fully attenuated . The flavors will subside after the beer has reached full attenuation. This can sometimes be the result of using too much cane or corn sugar or bacteria. Acetaldehyde is the last step in the fermentation process before ethanol is produced.
Solution: Age the beer for a week or two and if the green apple taste goes away then kudos. If not eliminate the use of corn and cane sugar. The sugar should be substituted with malt extract. Also starting with good quality yeast will help speed the fermentation process along and reduce fermentation time

Flavor: Butterscotch, Movie Popcorn, Slickness on tongue
Cause: (Diacetyl, C4H6O2) Like Acetaldehyde, Diacetyl is a naturally occurring part of the fermentation process, and over time will disappear if a proper attenuation is achieved. In small quantities Diacetyl is appropriate for some styles of beer. The diacetyl life cycle in your beer comes in two major steps, production and reduction. If either of these steps are interrupted inappropriate levels of diacetyl will be in your finished product.
  • Production: Diacetyl is the product of Acetylaldehyde and Pyruvate to produce α-Acetolactic Acid, which gives off hydrogen ions an CO2 to create diacetyl.
  • Reduction: Eventually diacetyl will change to acetonin, with an undesirable fruity, musty flavor, and then into 2,3-butanedoil which has no flavor
Solution: Properly oxygenate wort before fermentation. Make sure that you allow beer to have a "Diacetyl Rest" and wait for full attenuation before transferring (don't rack to early) . One strain of bacteria called sarcina grow rapidly during the end of fermentation and can irreversibly contaminate your beer with diacetyl. As always it is important to start off with health yeast and maintain a clean environment to avoid contamination.

Flavor: Cooked Corn
Cause: (Dimethyl Sulfide, (CH3)2S) DMS is caused by breaking down of S-methyl methionine (SMM), which is an amino acid caused by malt germination. This is not really controllable by you unless you germinate your own malt. Luckily for you, malt manufacturers have it down to a science an minimize SMM in your malt and malt extract. There will be some SMM in all malt but it can be removed from your final product by following a few
Solution: The main cause of DMS that you can taste is either not cooling wort fast enough or not having a rolling open boil. Any palatable DMS will evaporate during a minimum 60 minute boil if left uncovered, and rapidly cooled. DMS is also removed by gaseous CO2 during fermentation. If you have a weak fermentation the DMS removal will be weak so always start of with healthy active yeast.

Flavor: Skunky
Cause: (MBT, 3-methyl-2-butene-1-thiol) When humulone (The bittering alpha acid in hops) is exposed to light, specifically blue-green light (400-520 nanometer wavelength), a chemical reaction occurs creating MBT. MBT is part of the mercaptan family, along with the active chemical in a skunks spray, which gives it the distinctive skunky smell.
Solution: Do not expose wort or beer to direct sunlight after hops have been added. While sunlight can be the most damaging because of its intense light source (the freaking Sun), indoor lighting can cause the same damage to your beer. Keeping fermenter inside a dark closet or covered up will reduce MBT content, and NEVER use green or clear glass when bottling this is a recipe for skunk beer. (See: Corona for more details)

Stale,Wet Cardboard, Rotten or Old Vegetables, Sherry, Pineapple
Cause: (Oxidization, O2 -> BEER) When oxygen is introduced into your hot wort it creates aldehydes and produce the stale, cardboard flavor which is unpleasant for all drinkers.
Solution: To prevent oxidization avoid hot side aeration, which is when air is mixed in the wort at temperatures above 80°F. Only allow beer to be aerated after yeast has been pitched to aide in yeast aerobic respiration, after this has happened minimize any shaking or stiring of beer. During transfers from primary to secondary and secondary to bottles/keg is when the highest risk of accidental aeration occurs. Also only leave 1/2" to 1" of head space in bottles and use oxygen reducing bottle caps. If kegging be sure to completely purge air from head space by filling and purging 3 times. In higher alcohol beers this is generally perceived as "sherry" instead of cardboard, and(if style appropriate) not considered a flaw in many aged beer styles, such as barley wine and old ale.

Flavor: Astringent Mouth-puckering, like chewing on a grape skin, Metallic or Powdery
Cause: (Polyphenols known as Tannins, Catechin is shown below) Tannins are stored in grain husks and also in the skin of fruit, and when boiled or sparged with water over 170°F they are extracted. This is because the waters temperature is directly related to the solubility of its ingredients. Over-milling grain makes tannin extraction easier since the husks are further broken down making tannin extraction more efficient. High waters pH (above 5.2) can also increase tannin extraction. Mixing krausen into beer or transferring to secondary will increase tannins because of its concentration of the phenols.
Solution: Don’t boil, over crush or over-sparge grain, be sure to keep water below 170°F. Check your pH and make sure it is below 5.2 and avoid letting krausen get into beer.

Alcoholic/Hot spicy/Solventlike
Cause: (Fusel Alcohols, Ethanol with more than two C atom) Proponol (CH3CH2CH2OH) and Butanol (CH3CH2CH2CH2OH) and other fusel alcohols give beer an undesirable alcohol flavor in high quantities. However, in some beers this is an appropriate flavor, such as barley wines and some bocks. These undesirable/solvent like tastes can come from several sources like excessive yeast growth, high levels of ethanol not allowing proper fermentation, excessive amino acids, and high fermentation temperatures. In other words, when fermentation is is too fast or too strong it can overwhelm the ethanol flavoring. Also, if the yeast start to ferment amino acids instead of sugars the resulting alcohols won't be to your liking. Bacterial infections also can cause solvent-like tastes.
If style appropriate, drink it! If not, try chooseing a different yeast strain, some stronger yeast strains, meant for higher alcohol beers, can overwhelm a flavors and . AAlso maintain a sterile brewing environment and control fermentation temperatures. At temperatures above 80°F yeast produce a much higher concentration of the heavier, long chain fusel alcohols which are the abrasive to the palette.

Fruity (strawberry, pear, banana, apple, grape, citrus)
Cause: (Esters, Acid(*-C=O-OH) +Alcohol(*-CH2-OH)->Ester) Esters occur naturally when alcohols and acids are combined in the wort. These esters give a fruit-like flavor and aroma that are desired in certain beer styles such a lambics and sours.
Solution: In ales ester production is lowest at temperatures between 60°F and 65°F and high at temperatures above 75°F. For lagers the window is much lower with low ester production below 50°F and high esters above 55°F. Try a cleaner yeast strain. Oxygenate wort sufficiently to ensure yeast health. Reduce original gravity. Check hop variety for fruity characteristics and avoid carrying over excessive hot break into fermenter. Be sure to pitch a sufficient quantity of healthy yeast to avoid yeast stress.

Medicinal, Plastic, Band-aid
(Chlorphenol, Cl-C6-OH) The most likely cause of this taste is infection caused by poor sanitation. Can also be caused by using chlorinated water or not properly rinsing cleaning solution from brewing equipment. Sometimes whole hop usage can contribute to this off flavor if a high alpha acid hop is used.
Solution: Clean and sanitize all equipment for brewing. If you really think sanitation is not the issue check your water for chlorine also be sure to rinse off all equipment and make sure no bleach (should you unadvisedly be using it) is rinsed off. If your water has high chlorine levels in it boil the water for 15 minutes to drive out any chlorine.

Yeasty Bready, sulfury, yeast-like
Cause: (YEAST) C'mon really what do you think makes your beer taste yeasty? Large quantities of dead yeast are canabalized by their still living comrades. Yeast on yeast action releases bitter lipids, resins, nitrogen and sulphur containing molecules.
Solution: If beer is young let yeast properly flocculate and settle. Watch your transfer method and make sure not too much trub makes it into your new container. And ALWAYS use healthy yeast.


Pumpkin Transfer

I transferred my Pumpkin Pie Ale to the secondary fermenter today 9/25/10. The bubbling had slowed down to one bubble every 3 minutes so I decided it was time to transfer after 6 days. I tasted it and it was disappointingly pumpkin-less. I measured 1/2 teaspoon exactly to add to the primary boil I have a feeling that was too little. To make up for the lack of Fall taste I added an additional rounded 1/2 teaspoon of pumpkin spice to the secondary fermenter and placed it in the brew closet. Hopefully this will be enough to elicit the taste of pumpkin pie and Thanksgiving.

UPDATE: September 29, 2010. Tasted the beer again today and determined not enough spice yet. Added an additional teaspoon. Bringing total to 2 teaspoons of pumpkin spice.

UPDATE: October 1, 2010. Tasted beer for final time and pumpkin aroma is adequate so I bottled today. I have not covered bottling on this blog since I have always had kegs. But recently I have been spending too much money on brewing so I decided not to buy my final keg for the kegerator. I will cover my bottling methodology in a post coming soon. I measured my final gravity since it is good to track of gravity readings and I have been lazy up to now. This won't really tell me anything because I did not keep get the original gravity but I need to get in the habit of documenting original and final gravities.

UPDATE: October 1, 2010 PM. Foamed my first keg, the bottled blonde. So, I could have kegged the pumpkin ale. This is fine since I have not bottled in a while and it would be nice to give out some pumpkin pie ale. I have also wrote up a post about my theory on bottling.

Wednesday, September 22, 2010

Dihydrogen Monoxide in Beer

Water can be one of the most important factors when trying to brew quality beer. This is because the effect various ions can have on starch degrading enzymes in malt. This is really only a concern when involved in all-grain and partial mash brewing. Malt extract brewers don't need to worry about this because the manufacturer of the malt takes this into account during the production of the extract.
This is not to say that extract brewers don't need to worry about water chemistry because they absolutely do. Though it is more important to like the taste of your water with extract brewing. The quickest way to get poor tasting beer is to start off with poor tasting water.

Hard vs Soft Water
Water hardness as a scale was created a long time ago when people started using soap. Soaps ability to later is directly affected by its mineral content. Typically, high mineral content makes it difficult or "HARD" to lather soap. Inversley soap with with low mineral content is easy to lather, soft is the opposite of hard so they went with that. My guess why they went this way is because "easy water" sounds dirty. I don't know why it just does.

Ranges for water softness follows, water harness is not an exact science so this is approximate:
  • 0-50 ppm = Soft Water
  • 51-110 ppm = Medium Hard Water
  • 111-200 ppm = Hard Water
  • >200 ppm = Very Hard Water

Temporary vs Permanent Hardness
When brewing there are tho types of hardness to be concerned with temporary and permanent hardness. Temporary hardness is a measure of bicarobonates in water [2(HCO3)]. This hardness that bicarbonate ions add is called such because when boiled they are precipitated (made solid) and removed from the water.
Permanent hardness is a a measure of magnesium and calcium ions in the water, both of which will remain after boiled. Permanent hardness can be adjusted for if its ranges are outside of the norm.

If I started this sentence with pH would I have to capitalize the p? The acidity and alkalinity of a liquid is measured in pH on a scale from 0 to 14 with 0 being the most acidic and 14 being the most alkaline. In all grain brewing, enzyme conversion occurs best with a pH of 5.2 (Acidic) this can be attained with the addition of Calcium Sulfate (CaSO4) commonly known as gypsum.


Sodium (Na)
Half of the chemical makeup of common table salt this ion contributes to body and full mouth feel. The overuse of sodumn in water treatements will give a seawater taste to the end product. Generally levels of between 10 and 70 ppm are good for brew water.

Chloride (Cl)
The other half of table salt this ion releases malt sweetness and contributes to mouth feel and beer complexity. Generally ranging between 1 and 100 ppm should always stay below 150 ppm to avoid salty flavors

Calcium (Ca)
The most important chemical in "permanent hardness" this element helps lower pH and facilitates precipitation of proteins during boiling. Most beers should be maintained around 100 ppm any higher will create a harsh bitter taste.

Sulfate (SO4)
While second to calcium for effectively lowering pH, Sulfates take the gold for influencing hop extraction and bringing out sharp bitterness. The amount of sulfates suggested will vary depending on your beer style.

Magnesium (Mg)
Magnesium is primarily a yeast nutrient that should be maintained around 20-30 ppm. The addition of Epsom salts can raise Magnesium levels in water. However many experts advise against it because high Magnesium levels can lead to a dry, astringent bitterness in your final product.

Water can be adjusted to meet your brewing needs. Local home brew stores provide chemicals that can be used to adjust ion levels and change pH of your brewing water. Your local home brew store will know the water in your area and can make suggestions on what should be added if anything to your water. The following table shows how to modify your water:

Effect of adding 1 gram of chemical per gallon of water in PPM
Baking soda


Calcium chloride72



Epsom salts


Table salt



Here is the water chemistry of a few famous brewing towns (Expressed in PPM):

Mineral (Ion)
MunichDublinMilwaukeePortland, OR
Calcium (Ca)
Sulfate (SO4)
Magnesium (Mg)2-818-19411
Sodium (Na)3210127
Chloride (Cl)

As you can see different brewing cities around the world have very different water hardness and softness. This water hardness can change the taste of your beer a lot. When I toured the Deschutes Brewery, the tour guide explained that they put gypsum in their water so that it will taste like water from some town in England. Unfortunately, I didn't think to ask which town.

Hopefully this has been a good insight into water and how it affects the brewing process.

  • The Brew-Master's Bible The Gold Standard for Homebrewers - Stephen Snyder
  • The Complete Joy of Home Brewing 3rd Edition - Charlie Papazian

Monday, September 20, 2010

Tap Handle Three (Uno mas)

If there is one thing building this kegerator has taught me it is that Draft beer, though completely worth it, is expensive. I added my third tap handle to my kegerator this week. The final tap will have to wait since I went on beer buying bender on Sunday when I bought ingredients for my Pumpkin Pie Ale. Another tap handle and all nessacary equipment and ingredients made that a $100+ trip to the brew store. The tap handle can be seen to the right with his two new friends.

Stokes' Law and Order - Irish Moss Unit

This was originally going to be thrown in with my Pumpkin Pie Ale post because that was the first time I had used Irish moss but as I wrote it I decided that it deserved an entire post.

What is Irish Moss?
Chondrus crispus
or Irish moss as it's more commonly known is a species of red algae that grows along the coasts of the Atlantic Ocean.

Irish Moss: Why use seaweed in beer?
Irish moss in brewing is used as a fining agent which means it removes suspended particles in the beer that cause it to be cloudy. Sometimes the style of beer requires that you have suspended particles in the beer, hefeweizen for example, so Irish moss should not used.

There are two main causes of cloudy beer, proteins and yeast. When the yeast is at the end of its life cycle and most of the sugars in the beer have been consumed the cells will bond to each other, becoming heavier and dropping to the bottom. This process is called flocculation, and occurs naturally when the yeast go dormant. Not all yeast behave in this manner though, some will stay suspended indefinitely. A method of clearing beer further is to cool it down so that the yeast will go into hibernation mode and sink to the bottom. This is why white labs yeast are refrigerated to keep the cells alive but dormant until they are ready to be used.

There are two popular styles of Irish moss commonly used in brewing applications. Dried moss is just that, the seaweed is dried out, thrown in a jar and sold at brew stores everywhere. The other type is tabs, Whirflocis a brand of Irish moss that is concentrated and put in tab form. Whatever form that is chosen to add to the wort the implementation is the same, during the last 10-20 minutes of the boil throw in a tablet or about a teaspoon or the dried variety.

Stokes' Me, Stokes' Me
The principal used in determining the rate that suspended particles will fall out is called Stokes' Law. The equation is as follows:
V_s = \frac{2}{9}\frac{\left(\rho_p - \rho_f\right)}{\mu} g\, R^2

  • Vs is the particles' settling velocity (m/s)
  • g is 9.8 (m/s2) Assuming your not making space beer
  • ρp is the mass density of the particle (kg/m3)
  • ρf is the mass density of the wort (kg/m3)
  • μ is the wort viscosity (kg/m s)

Irish Moss can aide in this process by making the proteins and yeast stick together creating a heavier particle. Making ρp bigger will make the numerator bigger increasing the velocity that the particles settle.

Pumpkin Pie Ale

Pretty self explanatory I wanted to make a seasonal pumpkin ale for around Halloween and thanksgiving. Since pumpkin pie spice is the ingredient that elicits that response, guess what its called?

  • 9 lbs Light Malt Extract
  • 2.0 oz. Willamette hops (5% alpha-acid, whole leaf)
  • White Labs East Coast Ale Yeast
  • 1 lb. Caramunich (65°L, Crushed)
  • 4 oz. Belgian Aromatic Malt
  • 4 oz. German Melanoidin Malt (30°L, Crushed)
  • 1/2 Tsp. Pumpkin Pie Spice

On Sunday September 20th I purchased the all my ingredients through Main Street Homebrew Supply Co. and brewed that day.

Yada Yada Yada... If you are curious about what I did read my previous posts where I go into it in depth my method of brewing. I think I will mainly include deviations from standard brewing from now on. The ingredients and timing are also important so that will be included in all my write-ups as well as any thing different. As you can see to the left the standard generic boil photo.

One thing I did differently this time was to add Irish moss during the last 10 minutes of the boil. For you veteran brewers out there this seems like a rookie mistake, but my beer brewing teacher did not use it so therefore I never knew about it until I really started reading brewing literature.

For those not so veteran brewers Irish moss, or Chondus Crispus is a species of red algae that grow around the coast of the Atlantic Ocean. The reason for using this seaweed is because it acts as a flocculation agent and clears your beer. Read my post about Irish moss for the science that describes why this happens.

Hops/Ingredients Schedule:

QuantityIngredientBoiled for
1 oz.Willamette Hops Entire 60 min. Boil
1/2 oz.Willamette HopsLast 20 min. of boil
1/2 oz.Willamette HopsLast 10 min. of boil
1 tabIrish MossLast 10 min. of boil
1/2 tsp.Pumpkin Pie SpiceLast 10 min. of boil

For my Irish moss I used the Whirlfloc tabs, which some brewers scream about how it doesn't work and how the unmolested dried Irish moss is so much better and pure. I have never used the raw dried Irish moss so I cannot speak to its efficacy, but what I can tell you is that the Whirlfloc tabs definitely work. Withing 10 minutes of transferring my wort to the primary fermenter there was 2 inches of cloudy trub at the bottom of my fermenter. I have never seen this effect in my beers before. Within a day the suspended proteins had settled out completely. I used the tabs because they are a lot easier you just toss a tab in the last 10 minutes of the boil and forget about it. I don't know if i will eventually become a purist and switch to dried but for now I am amazed at how well the tabs worked so I will stay with that for now.

Pumpkin Pie Spice is very strong and you don't need very much this is a "less is more" situation where you can add more to your secondary but you don't want to add too much up front. In about 2 weeks I will taste the beer and determine if it tastes like Thanksgiving and determine if it needs more spice.


Ill bet at least one of you is wondering why there is not pumpkin in my Pumpkin Ale. This is because the pumpkin is the Tofu of Fruit. It has almost no flavor by itself and takes on whatever flavor it is spiced to. When you taste pumpkin pie almost none of the flavor is from the pumpkin. If you don't believe me when you're carving pumpkins this Halloween go ahead and take a bite out of the Jack-O-Lanterns eye and let me know how it tastes.

Sunday, September 12, 2010

Kegerator Upgrades

I recently made some minor functional and major cosmetic upgrades to my kegerator. Functionally, I moved the CO2 tank to the outside of the kegerator. This was accomplished by a brass pipe placed through a hole in the wooden collar with a 90° elbow and a barbed fitting on both ends(Outside: Left, Inside: Right). I placed a washer to take up some slack and to make a better insulated pass-through. This modification was made because I was having troubles with the tank not producing CO2 fast enough, it would sometimes take almost a minute to produce enough CO2 for the initial air purge when kegging (which has to be done 3-4 times). Another reason to move the tank outside is I recently acquired a 2.5 gallon corneilus keg and the mini corny and the gas tank would not both fit in the kegerator. This was an amazing find since these little guys are extremely rare compared to their 5 gallon counterparts. I found this one on craigslist for $75. A normal 5 gallon corny keg sells for between $30 and $40 where a 2.5 gallon one can sell upwards of $150, demonstrating the simple economics of supply and demand.
The cosmetic modifications were pretty major also.
I finally cut a hole for the thermocouple to pass through, it can be seen next to the barbed fitting on the inside of the chest. I finally got tired of looking at it just dangling over the edge. The other modification I made was to clean up the unruly routing of the gas and product lines. The easiest way i could think to do this was orient the kegs so gas lines were on the outside and product lines in the center. This turned out to work great and the results can be seen below.

Friday, September 10, 2010

Deschutes Brewery Tour

This weekend I went up to Bend to go to a wedding (which was ridiculous) and while there I decided it would be a good idea to take a tour of Deschutes Brewery. While waiting for the tour to start we sat in the tasting room and were given 4 free samples equivelant to that of about a flight. I believe they do this to facilitate learning on the tour.

After the tour started we were directed to look at the two MASSIVE silos in front of the building that contained malted barley. All the spent grain is recycled in some way whether it is in their bakery, that supplies the brew pub with buns and bread, or taken to a farmer that uses it as feed for cattle.

Once inside the building I see 2 gigantic tanks with the which are the tuns for the original brew house (Right: inside mashtun). Which are still in use today. The Next stop on the tour is the employee break room, where each employee gets refreshing beverages after their shift. There is a closet with rotating tap handles for employees enjoyment and to the right of this fun door is a much larger door. The next passage to Narnia is the Hop Room where hundreds and hundreds of pounds of whole leaf hops are stored preparing to be dumped in hot wort.
Deschutes Brewery uses primarily Cascade hops in their beer according to our less than helpful ditz of a tour guide. (Shown left molesting bags of hops.)

The next stop on the tour is the huppmann room. This room is filled with possibly the most impressive pieces of industrial equipment I've ever seen. These were gigantic tanks with conical tops and not a single seam on them. No seams/welds are important in brewing equipment because bacteria can get trapped in the rough areas of the welds, causing the beer to have undesired flavors. These tanks were designed, built, and shipped from Germany to Bend. They had to close down several sections of the highway to transport the tanks to their final resting place at the brewery. (Note: The picture at the right are not of Deschutes a bunch of damn tourists were in the way.) After this we went upstairs and saw the lab and blind tasting room continuing on to the fermenting room. Pictures below:

Following the fermentation room was the bottling room it seemed a little small for the thousands of bottles that get passed through those doors. After bottling upstairs we went to the office section where every Jubelale bottle design was put on the wall.