Gravity questions

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hinke

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Hi,

I just brewed my first IPA this weekend. Everything went almost according to plans. We just missed the Mash Temp, and had to add hot water to bring it up in temp.

Now, I took a gravity reading after draining the wort from the mash tun, and the gravity was low (I can't remember what it was, but I think it was like 1.040 something), but I thought this was the OG.

We then boiled for 60 minutes adding hops etc. I then took another gravity reading and it went up to 1.060, I was planning to hit 1.067, but I think we were pretty close. Is this the OG?

Can someone explain to me why the gravity increased when boiling the wort...

And, can someone explain to me what the final gravity should be that I am looking for?

I am just confused about all this.

Thanks.
 
You boiled off wort and concentrated it. You should expect a higher gravity after the boil. You,ve missed your OG by a little, but not horrible. Without knowing the recipe I can't say if your effficciency was low or maybe you had to much wort and didn't burn off enough. Your FG (final gravity) is your reading when fermentation is complete. You use your OG and FG to determine your abv.
 
Yes, the OG is the gravity after the boil and cooling. It will always be higher than the pre boil gravity because during the boil, you evaporate water (which has a gravity of 1.000), but not the sugars (which have a higher gravity); so you end up with the same amount of sugar, but less water.

-a.
 
It makes sense :) Thanks.

My recipe was 13 pounds of grains. According to beersmith it should have been at 1.067.

I got some channeling when draining the mash tun on the second run, and that might have messed things up a little bit. I could see that the wort drained at one spot. We stopped as soon as I saw it, and I pushed the grain bed a little bit and tried to stop the channeling.

Again, this was the first time I brewed a beer, and I started with all grain. It's fermenting like crazy now and it has a great krausen. I'm happy.
 
Congrats.:)
Just an FYI. Beersmith cannot tell you what your gravity should be until you tell Beersmith what your efficiency is. Now you have done a brew, you should be able to plug that number in, but it will probably increase a bit over the next few brews as you become more familiar with the process.
Sounds like you are batch sparging. If that is the case, and you stir the sparge water really well, you don't need to worry about channeling. That only applies to fly sparging.
Sounds like you got about 65% efficiency which isn't too shabby for a first brew.
Nobody really knows what your FG will be. If you can post the grain bill, mash temperature, and the yeast you used, we can take an educated guess, but I wouldn't worry if it is a few point off.

-a.
 
I'll get back to you with the grain build. It's on my other laptop...

Yes, we did batch sparging..

How do you calculate the efficiency?
 
I'll get back to you with the grain build. It's on my other laptop...

Yes, we did batch sparging..

How do you calculate the efficiency?
Take your OG, subtract 1.000 and multiply the difference by 1000 then multiply that by the number of gallons of wort in the fermenter
So 1.060 - 1 = 0.060 * 1000 = 60 * 5 (gallons) = 300.
Now divide that figure by the (number pounds grain * 36)
So 300 / (13 * 36) = 0.64 or roughly 64%

If you want to be a bit more accurate, consult https://www.homebrewtalk.com/wiki/index.php/Malts_Chart
For each malt, there is a "potential" value. Subtract 1.000 and multiply the difference by 1000, and use that number instead of the generic 36.
Or the other (easier) way to do it is to download Promash or Beersmith, and it does the math for you.

-a.
 
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