Author Topic: Gravity adjustment  (Read 6661 times)

Offline KB

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Gravity adjustment
« on: May 18, 2021, 02:53:16 PM »
What about gravity adjustment post fermentation? When I?ve had to adjust gravity, it was always after the boil kettle cooling, pre-fermentation. Over the past year, with covid (no we haven't have covid) we?re not drinking as much and friends, relatives, etc are not visiting. So, beers are sitting a bit longer than normal. I kegged a beer the other day and the FG was lower than I expected resulting in a higher than desired ABV (for the style. No, I don't want to call the brew "Imperial"). The BeerSmith tool makes it intuitively simple to determine how to adjust the gravity. However, if I add water to adjust the gravity, I am introducing oxygen? Probably not a good idea. Ignoring the oxygen input, what about ending up with a watery tasting brew? How do other handle this situation?

Apologize if I?ve posted in the wrong forum. If so, please move to the correct location.

Thanks.
« Last Edit: May 27, 2021, 07:38:43 PM by KB »

Offline BOB357

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Re: Gravity adjustment
« Reply #1 on: May 19, 2021, 03:28:52 AM »
Unless you're entering the beer into competition, style guidelines don't mean squat. Even in competition, unless the difference in ABV is distinguishable, it won't affect how the beer scores.
Bob

Offline KB

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Re: Gravity adjustment
« Reply #2 on: May 26, 2021, 04:17:08 PM »
My question has nothing to do with beer competitions. If I intended, for example, to make a "lawn mower beer" and the beer finished higher than desired, I, and probably most, will definitely realize the higher ABV.

Offline BOB357

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Re: Gravity adjustment
« Reply #3 on: May 26, 2021, 04:44:42 PM »
It was in the context of style, which is what I responded to.

"I kegged a beer the other day and the FG was lower than I expected resulting in a higher than desired ABV (for the style. No, I don?t want to call the brew ?Imperial?)"
Bob

Offline KB

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Re: Gravity adjustment
« Reply #4 on: May 26, 2021, 05:36:32 PM »
"Lawn mower beer" or "session beer" is a style. We should a be brewing with something in mind otherwise we're brewing to chaos.

Now days, for the most part, if someone f**ks up the brew's ABV, they call it "Imperial" and live with it. That's why I wrote about style and imperial.

Offline BOB357

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Re: Gravity adjustment
« Reply #5 on: May 26, 2021, 07:53:57 PM »
Sorry. My crystal ball isn't working well lately. Hopefully, you've come up with a solution.
Bob

Offline Kevin58

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Re: Gravity adjustment
« Reply #6 on: May 27, 2021, 06:40:44 AM »
This is why we take gravity readings throughout the brew day. You should know the expected pre-boil gravity, and the post boil gravity. If you check those during the brew session you can adjust before it ever goes into the fermenter.
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Offline jomebrew

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Re: Gravity adjustment
« Reply #7 on: May 27, 2021, 08:48:57 AM »
What @kevin58 said.

While I have a pretty predictable brew system and process, the wort does not always cooperate.  I often just document and go on not caring much if the gravity is too low or too high.  However, my periodic measurements allows me to know where I stand against predicted measurements. 

While I generally don't care, sometimes I do and will adjust along the way.  Recently, for some unknown reason, my initial runnings and, thus, second runnings and preboil gravity  were lower than anticipated.  To adjust, I boiled longer to evaporate off more water an concentrate the wort.  I stopped when it reached the target zone (was an additional 30 minutes of low, rolling boil). 

I have also added water at flameout to adjust a too high gravity but that was a time I didn't take frequent measurements.

There are ways to adjust along the way as long as you have data to work from. Be a data collector and enrich your life  ;D ;D

Offline KB

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Re: Gravity adjustment
« Reply #8 on: May 27, 2021, 07:39:33 PM »
I have plenty of data from my brew sessions. Really, not what I'm asking.

Offline Oginme

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Re: Gravity adjustment
« Reply #9 on: May 28, 2021, 07:20:29 AM »
Speaking of getting back to some of your original questions, I have been asking around to several brewers I know about dilution after fermentation.  This is not an uncommon technique and is commonly performed by many large scale producers of mass volume commercial lagers.  One of the keys is to pre-boil any water used for dilution and chill in a sealed container where air cannot be reabsorbed into the water.  Obviously, minimizing splashing and air contact is critical when performing the dilution.

Another thing to consider is that these beers are designed to be diluted.  The body and flavor of the base beer are higher such that the water added will not produce a product which is clearly watered down.  Much of the ability to get away with post fermentation dilution will be based upon how much dilution water you are looking to add. Taking a recipe where the FG ended up lower than expected and then adding an appreciable amount of water to bring the ABV into your desired target will depend upon just how much you need to move that needle.  Small dilutions may not be as readily noticeable as greater dilution quantities would be.  The biggest hit will be on the body of the beer and resultant mouthfeel which is what will really give the impression of being 'watery'.

Hope this helps a little bit.  Having never done this myself, there is not good direction I can give nor assurances of any success.

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Offline KB

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Re: Gravity adjustment
« Reply #10 on: May 28, 2021, 03:20:28 PM »
Perfect! Exactly what I needed. Thank you  :)