[dean]

How many of you do it on a regular basis?  I just did a batch purposefully topping up with water after the boil because I had to brew in the house and I also wanted to help chill the boiling hot wort immediately.   I've never tried it before except when I had been doing extracts or partial mashes... I'm curious to see what comes of it.   Those of you that have or are topping up regularly, have you noticed any benefits or disparities from doing it?   

I may have lost a tiny amount of efficiency but I'm not sure... with a 5 gallon boil topping up with cold water  to make 7 gallons in a bucket I still had 81% efficiency... 11 pounds of malts plus 1 pound of corn syrup and I have a OG of 1.051.  Having watered down by topping up, I'm expecting to get a lower FG than if I had done a full boil.  I'm not sold on what to expect from my hops considering the things we're learning about hopstands etc.  One calculation shows a higher IBU than if I had done a full boil...       No matter... I'll drink it anyway and I'm getting to where less means more to me lately anyway.   

[tomsawyer]

I will occasionally top up with tap water if I happen to overshoot my intended OG.  The beauty of small batches (3gal) is I always have room to do this.

Topping up doesn't affect efficiency, that only happens if you boil it.

[dean]

Yeh, thats one reason I did it... last summer I closed the gap on my mill and my efficiency jumped through the roof.  I get high 80's to low 90's for efficiency but I've also had issues with tannin extraction I think.  Maybe I just oversparged letting my pH level get too high at the end of the run-off... so figured I'd try this since I boiled inside the house.  Sorry to say I didn't take a gravity reading or pH reading of the wort until I had added everything together.

If this works... I may do it more often.  I figure I'll keg 5 gallons and bottle 1.5 to 2 gallons if all goes well.

[macadoon]

I top off almost every time. I tend to boil longer for for some flavor enhancement and my buckets are what they are. I also like the idea of adding water after the boil for some oxygen.

[dean]

I top off almost every time. I tend to boil longer for for some flavor enhancement and my buckets are what they are. I also like the idea of adding water after the boil for some oxygen.

Yeh, I boiled 90 minutes plus but only added hops the last 60 minutes and the corn syrup during the last 15 minutes.  Its been forever since I've used corn syrup too. 

[tomsawyer]

From what I understand, corn syrup can be kind of variable in its fermentability.  You're probably better off using cane sugar or rice syrup.

[bluesman]

I have topped off many times most often to reduce my OG but also to increase my volume. It's an easy method and it works well. Some may be worried about infections or other similiar problems but I've been doing it on a random basis for years without detriment to my beer. I try to target my gravity during the brewing process but sometimes I end up short on volume or too high on gravity and top off the beer to negate these issues.

[oscarvan]

As long as you have a place to go with it......I'f you're kegging 5 gallon increments is about it....

[Mark G]

I've done it many times with no ill effects. I brew outside, so sometimes it's tough to nail down the boil-off rate. For example, today, I added half a gallon at the end. I just use regular tap water through the sprayer for more oxygenation.

[tubercle]

Tubercle tops off in the boil kettle. The ol' trusty measuring stick tells where its at with about 5 minutes to go. If necessary the top off water is added then and let to come back to a boil. Cool, drain and pitch.

 Got to where its scary to boil too long. The efficiency might go through the roof.

[dean]

Got to where its scary to boil too long. The efficiency might go through the roof.

You bring up a good point, Tubercle.  Boil time can vary the efficiency perception but if you don't get the points from runoff out of the mashtun you're not going to get them from the boil kettle without adding sugars no matter how long you boil.  I lengthened the boil because I had to keep feeding wort into the boil kettle due to the kettle being small.  Then I diluted for two reasons, I wanted to cool the wort and lower the OG so I could ferment a larger quantity to keg and bottle.  Just messing around and seeing what can be done I guess, I probably won't be able to get around and do anything with it for 5 or 6 weeks.  I'm kinda wanting to do another batch before I go in but this one made a pretty good mess in the kitchen...