Keg Connection New Inline Flow Control Valve Giveaway

Home Brew Forums > Home Brewing Beer > Beginners Beer Brewing Forum > What controls the alcohol %
Thread Tools
Old 09-04-2007, 09:28 PM   #1
Feedback Score: 0 reviews
Join Date: Jan 2007
Posts: 20
Default What controls the alcohol %

I have made a few batches of beer from those can from coopers and when i measure the alcohol % its always a bit low like 3% i was wondering what controls the alcohol % so i can make them a bit stronger in alcohol

DerekPruder is offline
Reply With Quote
Old 09-04-2007, 09:33 PM   #2
Feedback Score: 0 reviews
Ryanh1801's Avatar
Join Date: Mar 2007
Location: Addison,TX
Posts: 2,713
Liked 12 Times on 9 Posts


In short the amount of extract you put into the batch. More sugar= more for the yeast to eat on.

Ryanh1801 is offline
Reply With Quote
Old 09-04-2007, 09:33 PM   #3
Beer Drenched Executioner
Feedback Score: 0 reviews
Mutilated1's Avatar
Join Date: Jul 2007
Location: Hoover, Alabama USA, Alabama
Posts: 2,195
Liked 38 Times on 26 Posts
Likes Given: 1


The amount of added fermentables is what controls the amount of alcohol. Like a Cooper's recipe calls for an additional 1kg of fermentables ( Cooper's dextrose, Cooper's brewing sugar, Cooper's brew enhancer, etc... )

Basically to make more alcohol, you just add more fermentables.
Mutilated1 is offline
Reply With Quote
Old 09-04-2007, 10:02 PM   #4
Feedback Score: 0 reviews
Join Date: Jul 2005
Location: Poo-Poo Land
Posts: 6,809
Liked 36 Times on 25 Posts


Let's not be short-sided.

OK, so the amount of fermentable sugar in the beer provides the potential for higher alcohol, but it's the alcohol tolerance of the yeast that determines the actual ABV. Weaker yeast cells die off from the alcohol level so ultimately the ABV is dependant on how tolerant the yeast are to alcohol.

Some yeast, like Turbo or Champagne and others can tolerate alcohol levels in the mid to high teens.

This is why people take gravity readings. At the beginning you can see potentially how high an ABV you could achieve. The final gravity reading shows how much sugar was converted prior to the yeast dying down to a level to where they can simply convert no more.

Also, the fermentability of the sugar plays a factor. Wort isn't just sugar and water, there's all sorts of matter that can't be digested by yeast. This is why wort can't get to the gravity of water or lower.

Honey can ferment to a level where the gravity is lower than water. Almost all of the honey is digested into alcohol, so the gravity can be (for example) .990 when water is 1.000.

Other times, brewers add non-fermentable sugars for "mouthfeel" (i.e. malto-dextrine) or to provide sweetness (i.e. Lactose).
Past Winners: Caramel Cream Ale #1, Hoegaarden Clone, Boom-Boom Vanilla Ale, Lazy Monk Abbey Style, Amarillo Cream Ale. (AG),

Buy a shirt now!!! Please! Did I help you? Buya shirt!
Cool Shirts.

Cheesefood is offline
Reply With Quote
Old 09-04-2007, 11:15 PM   #5
Feedback Score: 0 reviews
david_42's Avatar
Join Date: Oct 2005
Location: Willamina & Oak Grove, Oregon, USA
Posts: 25,678
Liked 143 Times on 135 Posts


A hydrometer does not measure alcohol percentage. The difference between the original gravity and final gravity can be used to calculate the amount of alcohol.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"

"I would like to die on Mars, just not on impact." Elon Musk
david_42 is offline
Reply With Quote
Old 09-05-2007, 02:05 PM   #6
St. Jon's Wort
Feedback Score: 0 reviews
Join Date: Aug 2007
Posts: 79

Originally Posted by david_42
A hydrometer does not measure alcohol percentage. The difference between the original gravity and final gravity can be used to calculate the amount of alcohol.

My hydrometer measures potential ABV by %. I currently have a bock in my primary and the O.G was 1.050 and it had 6.5% potential ABV.
St. Jon's Wort is offline
Reply With Quote
Old 09-05-2007, 02:20 PM   #7
Feedback Score: 0 reviews
Evan!'s Avatar
Join Date: Aug 2006
Location: Charlottesville, VA
Posts: 11,900
Liked 81 Times on 68 Posts
Likes Given: 1


Jon's Wort is right...those hydros (mine at least) has a little scale on there for measuring potential ABV. I never use that scale, but it is on there. I wouldn't rely on it myself, because it cannot take into account the tolerance of the yeast or the proportion of fermentable:unfermentable sugars in your wort.
Aristocratic Ales, Lascivious Lagers

•Scottish 80/- •Sweet Stout •Roggenbier
.primary | bright:
98: Moss Hollow Soured '09 72: Oude Kriek 99: B-Weisse 102: Brett'd BDSA 104: Feat of Strength Helles Bock 105: Merkin Brown
.on tap | kegged:
XX: Moss Hollow Springs Sparkling Water 95: Gott Mit Uns German Pils 91b: Brown Willie's Oaked Abbey Ale 103: Merkin Stout
98: Yorkshire Special 100: Maple Porter 89: Cidre Saison 101: Steffiweizen '09 (#3)
Evan! is offline
Reply With Quote
Old 09-05-2007, 02:37 PM   #8
Feedback Score: 0 reviews
CBBaron's Avatar
Join Date: Feb 2007
Location: Cleveland
Posts: 2,787
Liked 8 Times on 5 Posts


The potential alcohol scale on the hydrometer is for wine makers and distillers. The sugars in wine are nearly completely fermentable so the original gravity directly translates in to finish ABV. However beer is not completely fermentable so to get the actual ABV of the finished product you need to subtract the final potential from the original potential. Most brewers however just measure the gravity and use a formula or software to get the ABV.
As mentioned for most beers the ABV is directly related to the original gravity. To increase the OG you need to add more sugars. Adding simple sugar like table sugar will result in a dryer beer that can be watery. Adding malt extract will add body and sweetness which should be balanced with additional hops. If you ABV starts getting too high you will get more alcohol flavors and for really big beers the alcohol tolerance of the yeast starts having an effect.

CBBaron is offline
Reply With Quote
Old 09-05-2007, 03:23 PM   #9
Feedback Score: 0 reviews
landhoney's Avatar
Join Date: Apr 2007
Location: West Palm, FL
Posts: 1,359
Liked 6 Times on 6 Posts


I would say the brewer controls the abv%, but he delegates most of the actual work to his yeast slaves. They receive no pay, only receiving food and lodging. Some brewers treat their yeast well and get good results, while others do not and achieve poor results. Sorry, I'm in a weird mood.
landhoney is offline
Reply With Quote
Old 09-05-2007, 03:45 PM   #10
Feedback Score: 0 reviews
Join Date: Jun 2007
Location: The "Ville"
Posts: 1,921
Liked 10 Times on 10 Posts


You fools! As any good brewer knows, alcohol is controlled completely by the little gnome who lives in your airlock. I leave him cookies and milk each night and he makes my brew stronger. Sometimes I even tickle him with a feather to........

Oh! right! Yeast make alcohol. I suggest you read about them here.

The amount of "food" they can eat in the beer determines how much alcohol they will poop out. Also of note, is their alcohol tolerance. If you give them too much food they will not be able to process it all and your beer will be sweet.

The higher the OG the more POTENTIAL alcohol there is. The lower your FG, the more alcohol has been produced.

I have been successful in making REALLY high ABV brews.

BOTTLED: "Route 66 IPA" 7% ABV, "Dave's Imperial Stout" 12% ABV , "Spider Imperial Stout" 9%ABV , "Mutt Irish Ale" 7% ABV, "Sorta Sierra" IPA's 4.4% ABV, "Habanero Ales" 5.5% ABV, "Pumpkin Seed Ale" 5.5% ABV , "Marzen" Lager, "Step child Ale",
PRIMARies: "Caramel Amber" , "Black Porter"
SECONDARIES:1 :"Miller Ale"
On DECK: Another Russian Stout
cheezydemon is offline
Reply With Quote

Thread Tools

Similar Threads
Thread Thread Starter Forum Replies Last Post
Installing Johnson Controls A19 Gritsak Fermenters 7 09-08-2012 01:20 PM
Johnson Temp Controls daveooph131 Equipment/Sanitation 6 06-05-2011 04:32 AM
Need Help With Temperature Controls Madkins Fermenters 2 09-22-2009 12:45 AM
Fermenting Controls Finished! p-nut Fermenters 7 05-05-2009 03:57 PM

Forum Jump

Newest Threads