Boil after sparge

A few quick questions:

I'm fly sparging.

When collecting wort into my kettle, I am bring the newly collected wort to a slow boil to stop conversion - is this correct?

Here is my next question - after I collect say 50% or so of my wort, could I not start the clock on my full boil and add my first hop addition?

Heating the wort above 170 will stop conversion, so boiling definitely will.

I start the boil clock when all the wort is boiling, and generally boil for 10-15 minutes to get the hot break before I add any hops. No reason you can't do it your way, though you might lose some bitterness due to hop resins precipitating with the hot break proteins. Theoretically, you might get less isomerization of the resins due to higher gravity in the first runnings. I suspect this second effect is pretty minimal; more theoretical than actual.

Conversion should stop during the sparge, no? The conversion of starch in the grain is what you're stopping?

I wouldn't boil it until you get all your wort collected. Like AiredAle said, you can just bring it above 170 to stop conversion. If you boil half of it you risk carmelization of that part of wort I believe.

Also, if you collect 50% and start the boil timer, then when you add the last 50% of wort it won't be boiling anymore. You'll have to bring it up to boiling again...I don't know how that would affect your boiling times or hop utilization.

Just my $0.02.

I don't see any harm as long as you have enough wort in the pot to keep from burning the sugars. It's really no different than heating the wort from your mash while you are resting your grain in sparge water when you are batch sparging. The only thing I would suggest is not boiling your wort until you have collected it all. If you do, you are already evaporating water, and it could throw off your water calculations and hops utilization. But, this is debatable. As for stopping the conversion, I believe Airedale is correct. Once you hit 170 degs, you are stopping the starch conversion anyway.

Conversion of starch is not the issue, because you are right, starch to sugars should be done in the mash. The issue is further conversion of non-fermentable sugars that give "body" and "mouth feel" to the beer. These can continue to be converted during the post mash time if the temp isn't raised to denature the enzymes responsible.

If you're throwing in your bittering hops into only half as much wort while boiling your hop utilization is going to go down. If you can compensate for that then it should be alright.

AiredAle said:

. . . . . . The issue is further conversion of non-fermentable sugars that give "body" and "mouth feel" to the beer. These can continue to be converted during the post mash time if the temp isn't raised to denature the enzymes responsible.

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I don't understand this, isn't all enzyme activity halted by the sparge and/or the ensuing boil? Or are we saying the same thing?

Keep on brewing my friends

COLObrewer said:

I don't understand this, isn't all enzyme activity halted by the sparge and/or the ensuing boil? Or are we saying the same thing?

Keep on brewing my friends

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Depends on whether or not you do a mash-out, and what temperature you're sparging at. I don't do a mash-out, so the first runnings go into the kettle at mash temperature, and that wort continues to have enzymatic activity until I fire up the burner and heat it to over 170F.

I often decide on when to light the burner based on how accurate my mash temp was. If it was low or right on, I light the burner right away to lock in the profile. If the mash temps were a little high, I let the enzymes keep working until the sparge is done.

JuanMoore said:

. . . . I don't do a mash-out, so the first runnings go into the kettle at mash temperature, and that wort continues to have enzymatic activity until I fire up the burner and heat it to over 170F.

I often decide on when to light the burner based on how accurate my mash temp was. If it was low or right on, I light the burner right away to lock in the profile. If the mash temps were a little high, I let the enzymes keep working until the sparge is done. .

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I don't typically do a mashout either. I see what you're saying but for this to be true I would have to start draining prior to the mash saccarification being complete, I don't typically do that either. So the last part of your statement would only be true again if saccarification were not complete. The wort profile when I start draining is typically "locked in" already.

So, what I'm saying is that whether I miss the mash temp or not, it doesn't matter one way or another if I wait until saccarification is complete, I guess I can use this "draining prior to saccarification completion" as a tool, but I doubt it would make that much difference, especially since I typically batch sparge.

Unless of course I'm in a hurry, then I can make substandard swill with the best of them!:rockin:

Keep on brewing my friends

COLObrewer said:

...but for this to be true I would have to start draining prior to the mash saccarification being complete.

...The wort profile when I start draining is typically "locked in" already.

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The enzymes will continue to break down dextrin chains for several hours if you allow them to, so unless you're mashing for way longer than the rest of us, your first runnings aren't as locked in as you might think. The changes in the short time between the initial draining and the start of the boil are so slight that it really doesn't matter, but I'm a bit of a control freak.

JuanMoore said:

The enzymes will continue to break down dextrin chains for several hours if you allow them to, so unless you're mashing for way longer than the rest of us, your first runnings aren't as locked in as you might think. The changes in the short time between the initial draining and the start of the boil are so slight that it really doesn't matter, but I'm a bit of a control freak.

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Sounds good, lets brew!! I'll do a wee heavy next, "Poor scots strong ale", Gonna use all pale malt with a new caramelizing technique and hopefully yeast from juniper berries, it will be the least "controlled" brew I have done. What you brewing next?

Brew on my friends

JuanMoore said:

The enzymes will continue to break down dextrin chains for several hours if you allow them to, so unless you're mashing for way longer than the rest of us, your first runnings aren't as locked in as you might think. The changes in the short time between the initial draining and the start of the boil are so slight that it really doesn't matter, but I'm a bit of a control freak.

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Yeah, I thought about that, but I'm fly sparging, draining at 12m/G, so a typical wort collection takes me over an hour (longer than the actual mash).