OG question

Physics, chemistry and biology of brewing. The causes and the effects.

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OG question

Postby river water brewing » Mon Feb 09, 2009 4:14 pm

two fold question

I have a recipe that was supposed to give me an OG of about 1.051, when i brewed it (following the recipe to the letter)i had an OG of about 1.062, I am new, is that a big diference and how do you think it got so much higher

also i did a reading 12 hours after i brewed and the gravity was down to 1.051 could it have droped that quick?

the one thing i did was pitch the yeast in wort that was about 90 degrees +/- so i was worried about that but it did not seem to effect the feremntation as the air lock was bubbling

any thoughts are appreciated
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Postby slothrob » Mon Feb 09, 2009 7:32 pm

It's really common for people to get a not quite evenly mixed sample from a partial boil extract batch.
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follow up question

Postby river water brewing » Mon Feb 09, 2009 8:01 pm

thanks for the info!!! :D

BUT.... again because i am new to this i took a sample from the carboy after we mixed the 3 gallons of boil / wort to the other 2.5 gallons of water, the yeast was also added at the time the sample was taken.

should i have taken my OG reading from the 3 gallons of wort or from the total 5.5 gallons?

being as the wort i took the sample from was pretty mixed up, do you still think my ready was effected by a "thick" sample?

thanks again for the help!!!
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readings

Postby bfabre » Tue Feb 10, 2009 12:43 am

Take the reading from the 5 gallons. If you take it from the 3 gallons of wort it would be way high like 1.090 or something. If you have the ability try to do full boil.
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Postby slothrob » Tue Feb 10, 2009 7:59 am

You want to take the OG from the full volume.

I only mention this, not knowing how well it was mixed before the reading, because it is such a common problem. Also, for an extract beer, the only ways the OG can be off is if the recipe was calculated wrong, if you don't add all the extract, or if you don't measure the water correctly.

After a problem with the sampling, the next most frequent problem comes from getting the volume wrong; not correcting for volume shrinkage when cooling from boil to room temp, for example. But to go from 1.050 to 1.060, you'd need to have only 4.2 gallons.

It doesn't hurt to check that your hydrometer is correct, either. Double check that tap water reads close to 1.000.
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Postby jawbox » Tue Feb 10, 2009 11:20 am

Sloth you should really use distilled water to check the hydrometer. Also make sure you double check the calibration temperature of your hydrometer, some are 60°F others are 68°F. My buddy never realized this one when using the calculators in BTP.

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Hydrometer

Postby slothrob » Tue Feb 10, 2009 6:30 pm

Thanks for adding that, Jawbox. I shouldn't have assumed the poster knew about temperature correction.

Yes, you should use distilled water, but around here you get virtually the same reading with tap water as distilled. Your results may vary.
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Postby river water brewing » Wed Feb 11, 2009 12:05 am

thank you both for the info!!! so if i wanted to "Back Into" my OG, knowing that 12 hours after pitching my yeast the OG was 1.051, what do you think it would have been right after brewing?
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Postby slothrob » Wed Feb 11, 2009 7:13 am

If you think you hit the 5 gallon mark pretty accurately, I'd go with what the recipe said you would get. Also, I'd recalculate the OG from how much extract you added, to make sure the recipe was calculated correctly.

If you think you missed the volume, but know your actual volume, then the OG can be calculated from the recipe. Otherwise, I don't think there's any way to back calculate other than to assume not much fermentation might have taken place by 12 hours.

Also, check the calibration of your hydrometer in 60°F distilled water.

One thing is that the OG is less important than the FG, at this point, so don't worry too much if you missed it this time.
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Postby river water brewing » Wed Feb 11, 2009 1:23 pm

Thanks Rob!!! i did check my hydrometer and it is working good and i feel i did hit the 5 gal mark so i think i am very close to the 1.051 as i have used a few calculators to run the numbers.

I was just unsure how much ferementation can happen in the 1st 12 hours. I also wanted to try and get a ide of the og so that i can use the og and fg to figure what my V/V % is.

Thanks again!!!

PS
I am now 3 1/2 days into primary fermentation the krousen is starting to thin, yeast is starting to settel down to the bottom and i am getting about 6 bubbles per minute (i was getting almost 2 per second the first 24-36 hours). so i dont think i did to much damage when i pitched the yeast in to a slightly to warm wort.
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Postby Suthrncomfrt1884 » Wed Feb 11, 2009 4:14 pm

I think everyone gets a little paranoid when brewing their first few batches. I know I sure as heck did. Just remember the little things that you miss each time, and you'll learn to make it habit. My first few batches, I kept forgetting to take an o.g. reading, so I had to guess at my ABV. After getting annoyed with it, I eventually trained my brain to never forget.

Either way, you should have a drinkable beer, regardless of what your actual measurements were. Good luck, and let us know how it turns out.
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Postby slothrob » Thu Feb 12, 2009 7:19 am

river water brewing wrote:I was just unsure how much ferementation can happen in the 1st 12 hours.

That was the question I really couldn't answer other than to say somewhere between none and a lot. The variability between batches/brewers/yeast is just too great. In most cases, it's probably closer to "not that much", though.

I'd be honestly surprised if you weren't at 1.051, or very close.
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If it stayed that warm, it's ruined.

Postby billvelek » Fri Feb 13, 2009 3:58 am

slothrob wrote:
river water brewing wrote:I was just unsure how much ferementation can happen in the 1st 12 hours.

That was the question I really couldn't answer other than to say somewhere between none and a lot. The variability between batches/brewers/yeast is just too great. In most cases, it's probably closer to "not that much", though.

I'd be honestly surprised if you weren't at 1.051, or very close.

Actually, since 'river water brewing' said "... the one thing i did was pitch the yeast in wort that was about 90 degrees +/- ...", it wouldn't surprise me at all if a _substantial_ amount of fermentation occurred during the first 12 hours; in fact, I'd be surprised if it didn't, although I can't quantitate it because I've never fermented at that temp. Unfortunately, that batch will need to used for watering the compost pile, or it can be given to people who you want to discourage from ever asking you for another homebrew (a good way to discourage moochers). Sorry to tell you that, but let this be a learning experience. Drop your temp to as close to 68F as you can for an ale, and much lower for a lager. By the way, fermentation itself generates heat; fast fermentation generates heat faster. Unless you set your fermenter into a tub of cool water, it wouldn't surprise me if it didn't stay into the 80's the entire first 12 hours. Despite the optimism of others, I doubt it is drinkable.

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Postby jawbox » Fri Feb 13, 2009 10:11 am

I hate to say this but Bill is probably right. Even if this did ferment the amount of off flavors (esters and phenolics) would render this one undrinkable.

Follow Bills advice on lowering the tempt to 68°F before you pitch your yeast next time.
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Just to be clear, 74F is _acceptable_, too

Postby billvelek » Fri Feb 13, 2009 11:30 am

I'd like to qualify myself; while I've read numerous sources which have indicated that 68F is the _ideal_ ale fermentation temp (I think some might suggest slightly below that, like 65F, -- but that was probably for a particular strain) ... that doesn't mean that you MUST ferment at 68F. Frankly, I just ferment at room termperature in the house, but add evaporative cooling in the warm weather; that means our thermometer is set at just about 70F for heating purposes when we're home, and I'll drop it down to about 66F when we'll be gone for the day, and in warm weather I set the AC for about 74F. In warm weather I set my carboy in a large shallow tub with some water in the bottom and some towels wrapped around the carboy, and then I set a fan to blow on it. The water evaporates from the towel to cool the carboy, and the towel wicks up more water from the bottom of the tub. I will _occasionally_ drop a _few_ ice cubes in the water on days when I know that the temp in the house is a good 74F; however, be careful not to over do the ice cubes. Drastic swings in temp could shock the yeast, and if you drop the fermenter down into the low 60's, you'll probably cause the yeast to flocculate. I usually never 'monitor' the exact carboy temperature very much, and I don't think it is important to be really precise, so don't get too anal about it. My main goal is to try to keep the temperature low, and definitely keep it at or below 74F -- which I have set as my personal upper limit. I think some brewers might get away with letting it reach 75 or even 76, but the 80s is definitely too high. The warmer the fermentation, generally the more esters are produced, so beer fermented at 74 should be more estery than beer fermented at 68 but it will still be very drinkable -- just different. I don't mind estery beer, and it is an essential character for some styles. But when you get into the upper 70s, the yeast also begin to produce fusel alcohols which will cause bad headaches and hangovers -- even from just a bottle or two -- as well as create undesirable flavors.

Hope that explanation helps a bit.

Cheers.

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