High Gravity? What is it?

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk:

Mr.TC

Active Member
Joined
Feb 21, 2008
Messages
41
Reaction score
0
Location
Usaf Academy
I am new and have read a few books on how to make your beer high gravity, though I am lost on what it actually does. Could you let me know what the deal is. High grav vs. reg beer?
 

malkore

Well-Known Member
Joined
Jun 15, 2007
Messages
6,924
Reaction score
53
Location
Nebraska
and to quantify this further, a general guideline of 1.060 is when beers start to be considered 'high gravity'.

You'll get different opinions on what gravity qualifies as 'high', but generally speaking 1.060 is high enough that dry yeast will have problems rehydrating at that level becuase they can't pull liquid into the cell walls as easily.
 

Bills Brew

Well-Known Member
Joined
Jan 2, 2006
Messages
128
Reaction score
2
Don't mean to hijack this thread, but:

Do high gravity beers and dry yeast take longer to ferment to completion?

Make a stout with IG=1.072 and Nottingham yeast. Also had 9# of LME and 1# of DME. Fermentation kicked off pretty good at the lower end of the temperature range 3 weeks ago. Now, there is no Krausen, and virtually no air lock activity, but the gravity keeps dropping gradually. My experience with Nottingham yeast was that it took off fast, fermented hard (use a blow off tube), and finished within a week. I'm just waiting it out now.
 

malkore

Well-Known Member
Joined
Jun 15, 2007
Messages
6,924
Reaction score
53
Location
Nebraska
high gravity beers take longer to ferment, period. yeast is yeast, and the more sugar it has to convert, the longer it takes. as alcohol levels increase, fermentation also slows.

3 weeks a long time for 1.072 though. How well did you aerate the wort prior to pitching? add any yeast nutrient?? what temperature is the fermenter at? what's the gravity right now??
 

PseudoChef

Well-Known Member
Joined
Apr 18, 2007
Messages
3,401
Reaction score
117
Location
West Chicago 'Burbs
malkore said:
high gravity beers take longer to ferment, period. yeast is yeast, and the more sugar it has to convert, the longer it takes. as alcohol levels increase, fermentation also slows.

3 weeks a long time for 1.072 though. How well did you aerate the wort prior to pitching? add any yeast nutrient?? what temperature is the fermenter at? what's the gravity right now??
This isn't exactly true if you take into account pitching of the proper yeast cell count for the desired beer. My 1.092 888 RIS fermented out in 3 and a half days. It's been my highest gravity to date and the quickest ferment.
 

Bills Brew

Well-Known Member
Joined
Jan 2, 2006
Messages
128
Reaction score
2
Gravity now is 1.026. The wort was aerated by pouring from the kettle into the bottling bucket and then pouring from the bucket into the carboy. No, I didn't add any yeast nutrients. Initial fermentation temp was around 56^F for about a week then moved to 63^F, where it has been for two weeks.
 

9/9

Collembola!
Joined
Dec 6, 2007
Messages
416
Reaction score
8
Location
Durham, NC
I am about to brew a recipe with an estimated OG of 1.068. Should a single pack of rehydrated Nottinghams be okay?
 

PseudoChef

Well-Known Member
Joined
Apr 18, 2007
Messages
3,401
Reaction score
117
Location
West Chicago 'Burbs
9/9 said:
I am about to brew a recipe with an estimated OG of 1.068. Should a single pack of rehydrated Nottinghams be okay?

I would think so.

A single pack of S-05 took a 1.080 I did down to 1.017
 

menschmaschine

Well-Known Member
Joined
Jun 6, 2007
Messages
3,259
Reaction score
49
Location
Delaware
maltMonkey said:
high gravity = more fermentable sugars = higher alcohol content
We should mention dextrins here, too. This more applies to all-grain, but a high OG beer with a lot of dextrins won't necessarily yield more alcohol. High OG w/ normal or low anticipated FG = more fermentables = higher alcohol.
 
Top