What determines Boil Times?

What determines Boil Times?

I always done extract kits and did the 60 minute boil. I am getting ready for All Grain and was curious what determines the Boil Times.

I can't give you everything here (because I'm no expert), but one of the big reasons to boil longer is to reach a certain gravity. Let's say you want 6 gallons of wort for primary and want your OG to be at 1.060, but you collect 7.5 gallons at 1.051 (this is just an example and is not the correct answer in this case). If your evaporation rate is .5 gallons per hour, you would have to boil for 1.5 hours to get to the end result.

I boil based on my hopping and ingredients. I might boil most of my batches for 60 minutes, but I boil the Arrogant Bastard clone for 90 for the most bittering I can get as well as reducing the volume. Also, when I use a recipe with pilsner malt, I boil 90 minutes. Pilsner malt is notorious for producing DMS and needs a longer boil to help evaporate that out. Those are usually the only times I vary from the 60 minute boil, though.

what Yooper said Also, you can use a longer boil when you want a more carmelized wort (in a bock, for example).

I've been thinking about trying a 30 minute boil for my American wheat (50% wheat, 50% American 2-row) because it has almost no hops and I don't think it really benefits from a full 60min boil....

It's something like:

1. To extract bitterness from the hops and it's agreed that longer than 60 minutes would be diminishing returns. You could boil for less time and use more hops but there's a shortage going on.

2. To acheive a reasonable concentration of the wort through boil off. In a 5.5 gallon finished batch, you would normally start out with 6.75g of wort.

3. For pilsner malts, a 60-90 minute boil gets rid of DMS precursors. Some people tend to go for 90 minutes in this case just to be sure.

Bobby_M said:

3. For pilsner malts, a 60-90 minute boil gets rid of DMS precursors. Some people tend to go for 90 minutes in this case just to be sure.

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Are they any issues of excessively boiling wort (prior to adding hops)? Here's why I ask: For my first all grain batch I totally goofed and missed my mash-in target temp. I ended up adding an extra gallon or so of strike water to achieve the proper mash-in temp. Not wanting to miss out on effieciency I still used the recommended amount of sparge water. Long story short: I ended up with nearly 8 gallons of wort for a 5 gallon batch. I boiled off about a gallon and a half before adding my first hop addition because I knew that 60 minutes of boiling was not going to get me down to the correct volume and gravity. It eventually worked out and I got to the right OG and nearly the right volume, but I bet I was boiling that wort for about 2.5 hours because of that mash miss. (FYI: AG batch #2 went much better and with much greater precision)

Hopefully this isn't threadjacking, as it still seems kinda relevent to the title.

it may turn out darker than it would have normally.