What am I doing wrong?

Hi!
I would dilute a finished beer, but I would be happy to defer to wiser heads.

I brewed a full extract last month, I ended up 1.5l short and high on og. I was going to top up before pitching but I totally forgot and put it away in the fermentation fridge. I was debating if I should top up after, I didn't think it was a good idea as the water I was adding would be full of oxygen, I added it anyway as I was corny kegging it and would probably drink it long before it would spoil. I would add it before fermentation is finished, otherwise I would view it as you are essentially introducing oxygen to your brew. Or just leave it, I'm sure it will be damn tasty as it is. Just get your next brew on asap.

Jakeyboi said:

I would add it before fermentation is finished, otherwise I would view it as you are essentially introducing oxygen to your brew. Or just leave it, I'm sure it will be damn tasty as it is.

Click to expand...

+1 on this.

Hi Jon, I’ve just read the messages posted on your question about a reduced SG after you had mashed. There’s a critical temperature band to mash as has already been explained but it’s basically from about 63c to 69c. If your using a modified malt protein rests are not really needed but that depends on the grain. One thing that’s not been mentioned which is also very important in the mash PH value. That needs to be around the 5.1 to 5.4 depending on what’s being brewed. Conversion of sugars during the mash and also due to its effect on finished beer. Mashing should always take place at a pH between 5.1 and 5.4. I do treat my water for specific beers and monitor both temperature and ph, I had my water analysed twice and can predict the ph quite accurately. The temperature will determine the type of sugars that are dominating the finished wort and that in turn will effect the speed of fermentation, mouth feel, alcoholic strength plus taste. The sugars are fermented in a specific order, the simplest sugars are fermented first to the unfermentable dextrins. If I remember right they go in this order, Glucose, Fructose,Maltose, Maltriose, dextrins ( unfermentable). I’ve posted about managing gravity on here before as it’s quite easy to calculate without using BeerSmith. It’s good to have an understanding of how it works so I’ll cut and paste it again for you to have a read.

Hitting Target Gravity

Evaluate the total gravity during the brewing process and use it as a guide in adjusting the wort to the exact gravity you want. Remember that total gravity is the product of wort volume multiplied by its measured gravity in gravity units. As an equation, it is stated thus:
Total gravity = GU × Volume gallons

An important characteristic of total gravity is that it doesn’t change as you boil or dilute your wort. The only way to change the total gravity is to add fermentable materials such as malt extract, honey, or sugar to the wort.

By knowing the volume and gravity of the starting wort and the expected final volume of the boil, you can tell what the gravity of the wort will be at the end of the boil. Thus:

Total gravity (beg. of boil) = Total gravity (end of boil)

Because this is true, you can also say that

GU (beg.) × Volume (beg.) = GU (end) × Volume (end)

If you now divide both sides of this equation by volume (end), you get an equation for estimating the final gravity of the brew. Thus:

GU (beg.) x Volume (beg.) = GU (end)
Volume (end

Say you have 8 gallons of runoff from the mash. The specific gravity of this wort is 1.038. You plan to boil long enough to yield 5.5 gallons of finished beer. Because the total gravity will not change during the boil, you can calculate the finishing gravity of the boil:
(38 GU × 8 gallons) ÷ 5.5 gallons 55.3 GU

This calculation tells you that this wort will have a gravity of 1.055 when boiled down to 5.5 gallons.

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Jakeyboi said:

I brewed a full extract last month, I ended up 1.5l short and high on og. I was going to top up before pitching but I totally forgot and put it away in the fermentation fridge. I was debating if I should top up after, I didn't think it was a good idea as the water I was adding would be full of oxygen, I added it anyway as I was corny kegging it and would probably drink it long before it would spoil. I would add it before fermentation is finished, otherwise I would view it as you are essentially introducing oxygen to your brew. Or just leave it, I'm sure it will be damn tasty as it is. Just get your next brew on asap.

Click to expand...

agreed if you're using cold water. if you boiled it and let it cool then the dissolved oxygen has gone anyway.