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Old 03-16-2009, 04:32 PM   #1
Feb 2009
Posts: 16


I now have 2 AG batches under my belt (both Edwort's Haus Pale Ale).

My question regarding boiling is this: why does it matter what you end with? Why not just top off with water?

I did the haus pale ale recipe for a 5 gallon batch (it's listed for 5.5 gal). I only have a 5 gallon pot, and so I split part of the boil into 2 pots until enough had boiled off that I could fit it all into one. At the end, I have about 4ish gallons. I pour it into the carboy (5 gal), and top off with water. Then I take a gravity reading.

As the water boils off, you're really not losing any sugars, just water. Your sugars are just getting a little more concentrated.

I guess I just don't see what the difference is between starting with 6.5 gallons at your boil and ending with 5, or starting with 5, and ending with 4, and then topping off to 5. Is there a difference?

On a side note, the first AG batch I did (first brew in about 8 years) turned out to be a light pale ale - I milled the grains in a food processor and got horrible efficiency - about 45% - combined with essentially no sparge. It's actually quite good, but low alcohol, and very refreshing. It would be great on an august day when it's 95 outside.

I got 72% this time with a decent sparge and milling with a philmill.

Thanks for the info!


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Old 03-16-2009, 04:58 PM   #2
RedIrocZ-28's Avatar
Oct 2008
Grand Rapids, MI
Posts: 845
Liked 29 Times on 22 Posts

Yes, there is a reason. Hop utilization will differ if you are boiling in 1.040 wort as opposed to lets say 1.060 wort.

Also, adding topoff water changes your OG. Therefore changes how your beer would have tasted. Lets say you have 4 gallons of 1.040 wort and add a gallon, now you have 1.035 wort. The beer will be thinner, less body and mouthfeel etc.

Moreso, the reason people try not to have to use topoff water is because they are trying to create a technique and process that is repeatable. If you can predict exactly your outcome, you have effectively done quality control, And there is no need to correct after the fact. In the end its still beer but these are some reasons.

Oh, another arguable fact is that full boil beers taste better than partial boils with a top-up.
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Old 03-16-2009, 05:45 PM   #3
Feb 2009
Posts: 16

Thanks for the info. I didn't realize about the full boil actually tasting different.

But in regards to sugar levels and OGs, I don't get it. Forget about grains, etc. If I put a 5 pound bag of sugar in 4 gallons of water, boil for 1 hour and end up with 3 gallons of water with 5 pounds of sugar, then transfer this to a carboy and top off with 2 gallons of water I have 5 gallons of water with 5 pound of sugar.

On the other hand, if I put 5 pounds of sugar into 6 gallons of water, boil for an hour and then end up with 5 gallons, xfer, etc I have the same as above - 5 pounds of sugar in 5 gallons of water.

I don't see the difference in that respect. I guess I'll just have to wait until I have a larger pot to determine the taste difference for myself.

I guess I'm not that picky. If it tastes good, I'm happy.

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Old 03-16-2009, 07:13 PM   #4
Edcculus's Avatar
Jun 2007
Greenville, SC
Posts: 4,546
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You are right with your sugar in water theory. There is a lot more going on in beer than sugar and water though. Like RedIroc said, hop utilization will vary. The brewing programs assume you will be doing a full boil. If it gives you 30 IBU's with a full boil, you won't get the same if you do a concentrated boil and top off.

In addition to hop utilizatation, boiling creates Maillard reactions. If you boil a concentrated wort, you run the risk of getting some caramelization. This is not something you want in most beer. Its not as much of a problem with AG, even in your method. Just something to look out for.

Partial boils are a good option if you don't have the space. It all comes down to is brewing beer, or brewing the best beer possible.

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