stupid question........full boil?

[gator]

would someone define/describe a "full boil" and how this makes for a better beer?

gator

 

[BruDaddy]

Full boil is basically where your boil constitutes the full batch. In other words, when you rack the wort to the primary, you don't add any water to fill to 5 gallons (or whatever your batch size is). Not sure of all the benefits, I'm 100% extract brewing so far, but I've read that all grain brews must be full boils, though I don't know why. For extract brewing, it seems the main benefit of full or near-full boils is in hop utilization. The more you boil, the better hop utilization. In other words, you get more bang for your hop buck. Not sure I understand the physics of it, but I supposes it's sort of like brewing coffee. If you want 10 cups, you'll get a much better pot of coffee if you run 10 cups of water through the coffee grounds than if you run 5 cups through and then top off with 5 more cups of plain water.

 

[Professor Frink]

BruDaddy is right, full boils are needed for complete hop utilization. Essentially, you need to add more hops to a 2.5 gallon boil than to a 5 gallon boil to get the same IBUs. You need a full boil for all grain due to the fact that you will need to use that much amount of water to convert all the starches to sugars, then to rinse all the sugars from your mash tun to the kettle. If you end up using less water, you'll not obtain all your fermentable sugars and you'll have a lower OG when you top up the fermenter.

 

[bradsul]

When extract brewing a full boil will also help reduce the amount of carmelization of the extract. This will allow you to make lighter coloured beers. The late extract addition method will help in that regard if you do partial boils. As was also mentioned, it makes for much better hop utilization which means less money on hops (again the late extract addition method can help you with this when doing partial boils).

 

[homebrewer_99]

BruDaddy is right, full boils are needed for complete hop utilization. Essentially, you need to add more hops to a 2.5 gallon boil than to a 5 gallon boil to get the same IBUs. You need a full boil for all grain due to the fact that you will need to use that much amount of water to convert all the starches to sugars, then to rinse all the sugars from your mash tun to the kettle. If you end up using less water, you'll not obtain all your fermentable sugars and you'll have a lower OG when you top up the fermenter.

That's only partially true. Full boils are NOT necessary for complete hop utilization, but you are correct in your other statements.

Hop utilization is based upon the density/gravity of the boil.

If you do a reduced water and add all of your malt in then I can agree that you need to use/add more hops than usual. That's because the gravity is too high.

I start with 1.5 gals of water, but end up with less after the boil.

If you reduce your desity/gravity (use less malt), as I do, then you can use fewer hops.

The max hops utilization is 1 gal of water with 1 lb of malt (which is a gravity of 1.040), boiled for 1 hour is 30% bittering. That's the max. Even 90 min boils extract only 30% of the bittering acids from the hops. See page 258 in Papazian's 3rd ed of TCJOHB.

 

[Cheesefood]

Full Boils also release a lot more of the chlorine from the water, so your overall finished product will have less chlorine damage.