Okay to use top off water with AG?

[smalltown2001]

I know in extract brewing you can use top off water and the recipe is formulated so that with the dilution your gravity comes out right. I've had a problem with my AG batches though, that I end up with only about 4 gallons of wort at around 1.060, when shooting for 1.050. I know that I've been getting about 80% efficiency, so I should scale my recipes accordingly. And lately I've just used bottled purified water to top off the wort to get about a 1.050 OG. And it's worked great, I don't get stressed about boiling off too much, and I don't end up with a beer that puts you to sleep. But will this pose any problems for me in the future? I just realized that I might not be getting the best hop utilization, and maybe it will water down the flavor. Any experience with this? Thanks

 

[Catt22]

You can top off an AG brew the same way as you sometimes do with an extract batch. There is essentially no difference once the wort is in the kettle. Wort is wort at that point. Yes, your hop utilization may vary some, but you can compensate for that fairly easily if desired. The main thing when topping up is sanitation. The risk is minimal when using the bottled water, but I would boil any tap water before using. I've done it more than a few times without boiling, but there is some risk of contamination for sure. The flavor of the beer won't necessarily be watered down any more than the gravity will be, but that is to be expected with any kind of dilution. I would think the most direct approach would be to adjust your methods so you don't come up short every time. That should be easy to fix.

 

[samc]

Bottled water has been shown to be as contaminated if not more so than tap water in many studies. You might never have a problem but it could bite you sometime. Best bet is to adjust your recipes and techniques so you don't add any top off water. Shoot for 6 gallon brews and don't sweat it.

 

[chefchris]

Adjust your evaporation rate. It took me forever to get mine right. I boil off 1.5 gallons an hour.

 

[Revvy]

I have topped off a couple batches if I have miscalculated my boiloff (especially if I am doing a 90 minute boil to blow off dms, I end up short). Usually it has been no more than anywhere from a quart to a 3/4 of gallon or so.

And the amazing thing is that when I use the dillution tool on brewsmith, taking a hydro reading, and the total volume of the wort I have, and using the calculator for the half or 3/4 gallon I have needed, I end up with the exact OG I am supposed to have.

Pretty cool.

 

[Catt22]

I have topped off a couple batches if I have miscalculated my boiloff (especially if I am doing a 90 minute boil to blow off dms, I end up short). Usually it has been no more than anywhere from a quart to a 3/4 of gallon or so.

And the amazing thing is that when I use the dillution tool on brewsmith, taking a hydro reading, and the total volume of the wort I have, and using the calculator for the half or 3/4 gallon I have needed, I end up with the exact OG I am supposed to have.

Pretty cool.

This is pretty simple math that most fifth graders should be able to handle. ie
V1 x G1 = V2 x G2 One way to help avoid the possible contamination problems is to add the top off water before the end of the boil.

 

[Revvy]

This is pretty simple math that most fifth graders should be able to handle. ie
V1 x G1 = V2 x G2 One way to help avoid the possible contamination problems is to add the top off water before the end of the boil.

Even "simple math" as you say may be simple for YOU, not everyone is wired to think mathematically. I have always had a difficult time getting my head around math, I am more linguistically inclined. So I am grateful for programs and software that does the math for me in less than a second.

Where math is concerned, I am definitely not smarter than a fifth grader. But since I have a masters, AND have been published, I think I've done ok without being able to calculate the dilution ratio off the top of my head.

And unless you have either marked your kettle accurately OR have a refractometer which can calculate the gravity from a quick cooled drop of wort. Most folks take their post boil gravity reading from a chilled hydrometer sample, or drawn just before they pitch the yeast after employing their chiller.

So there would not be a "boil" to add the tiny amount of top off water to. And adding top of water to an AG batch is no different sanitation wise that it is to topping off an extract batch, you will find that a great majority of brewers have successfully topped off with 2.5 gallons of un boiled, un bottled tap water with no ill effects.

 

[mummasan]

Right, math for me is never a sure thing but I like not using a computer program to figure out my brewing details. I have been getting over 80% eff and want to be able to adjust wort on the fly to get the BG and OG that I am expecting. But like you, Revvy I don't have a refractometer and my kettle is not marked (for that matter my carboy isn't marked either).
I usually collect 6.5 gallons into the kettle (I measure with a dipstick). For my next brew I am going to collect 5.5 gallons in the kettle and keep the last gallon aside in a separate pot. I'm going to take the gravity reading from the 5.5 gallons and decide what to do from there. If the BG is high I will add water to the wort to bring it up to 6.5 gallons.