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Right Amount of Water to Add to Wort in Primary?


A very basic question that I struggle with on every batch of beer is how much water to add to the wort in the primary before pitching the yeast? I’ve suspected for a while that I may be diluting the wort to the point where the OG is below what the recipe calls for, resulting in a weaker tasting final product.

Most of the malt extract kits are built around 5 gal recipes-usually starting with 3 gals in your brewpot for steeping, boiling with hops, cooling, then pouring into the primary. However, if you boil water for 1hr in the brewpot, you end up with less than 3gal (not really sure how much you lose in the process).

After cooling, I add the wort to the primary and usually fill my fermenter to the 5 gal line, but don’t check the OG during this process.

Should I be adding water, and checking the OG of the wort several times during the process to make sure it doesn’t fall below the OG specified in the recipe?

And, if that’s the case, do I stop when I’ve reached the OG of the recipe, even if the total volume in the fermenter is less than 5 gals?

Thanks for the help on this. I’m fine if you all tell me I’m overthinking this, and it’s not an issue.

Mark the volumes on your fermenter. Fill it with 1 gallon of water and mark it, add another gallon and mark it again, etc until you reach the top of the fermenter. Then once you put your concentrated wort in the ferment you can just continue to add water until you reach the 5 gallon mark. Then thouroghly mix the water and wort prior to taking you gravity reading.

If you are putting all of the malt extract into your boil, and it is for 5 gallons, and you you are transferring all of the boiled wort . . . .it should be impossible to “miss” the intended gravity in my opinion. Water might evaporate from your boil - but the sugar does not evaporate, and that is where your gravity comes from.

Take a reading to be sure - but I don’t see how you could go under your gravity using extract if you have the correct total amt. of water.

If you find yourself wishing your beer was a bit heavier - just add an extra pound or so of appropriate DME to your boil and that will kick your gravity up.

In my experience, anyting under about 1.05 tends to start feeling a little “thin” to me. Additionally, I add .5 lbs of wheat and .5 lbs of oats to 80% of my beers to make them feel “full.” I do brew all-grain, so not sure if that would translate as well steeping in extract or not.

I agree that you should mark your fermentor so that you can have a reasonable idea of how much liquid you are adding, but the most important aspect of hitting a recipe correctly is to aim for the gravity points. When I used to brew extract, I would add the wort and add enough water to reach 4.5 gallons, stir well with a sanitized spoon and take a reading. Usually at this point, the gravity is only a few points under the intended gravity for the recipe. Simply add more water in small amounts (2-4 cups per addition) until you hit the number. Eventually you will get a feel for how much more water is needed per addition. There are so many factors that play into your evaporation rate during the boil, so don’t worry so much about the final volume, but rather the original gravity. Hope this helps.

For a partial boil, I start with 3.5 gal in the kettle. I usually lose about a 1/2 gal or so during the boil depending on the weather as I boil on the patio. Before adding the wort to the carboy, I first pour in 2 gal of cold water, then the wort on top of that, then top off with additional water if needed to get to the 5 gal mark I have on the carboy. 7 batches in, I’ve never missed the OG.

This is what I did…

While the wort is boiling I took the 5 gallons of star san in my bottling bucket and poured it into my fermenting carboy. I then mark the spot with tape. Now you know where 5 gallons is in a 6 gal carboy :slight_smile:

I then pour the all the star san back into my bucket and the carboy is now sanitized :slight_smile:

I then put 2 gallons of cold water into the carboy…then put in the wort after the boil and then add more water if needed to bring it up to the tape…whala…5 gallons of yummy beer. I checked my OG and it was spot on, 1052!

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