Purpose of the boil after mashing?

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robertbartsch

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OK, so during the grain mash the starches from the barley grain are converted to sugars and subsequently the wort is boiled for typically an hour.

Other than allowing added hops to provide some bittering and aroma, does the boil serve any chemical purpose, for example, does it change the composition of the sugars or is the boil merely done in brewing to blend or enhance the malt flavors?

I mostly brew using extracts but often I also mash in grains (e.g., PM brews) and this is mostly done in a separate pot which I then add to the extract boil.

My question is really; do I need to boil the separate grain mash for one hour if I will not be boiling the "extract sourced wort" for more than a few minutes?

Thx...
 
There's going to be some caramelization of the sugars, also the wort will become more concentrated, and it sterilizes the wort (although that probably only takes 5 minutes). Of course the addition of hops to the beer is an important part of brewing and boil time and wort gravity during boil will both affect the final bitterness of the beer as well as the aroma and flavor. Of course you could just use hop extract if you really wanted, but in my opinion that would take away some of the fun.
 
I think the angle he's going for is you could technically add a bit of extract to some water, boil that and the hops for 60 minutes while the minimash is mashing. You could then add that and the rest of the extract at the last 15 minutes. It could potentially save time for low IBU beers, but I'm guessing only about 30 total minutes. Your hop utilization would be pretty low though and you'd suffer pretty low efficiency on the mashed part of the wort.
 
OK, so during the grain mash the starches from the barley grain are converted to sugars and subsequently the wort is boiled for typically an hour.
Also just to clarify, during the mash, you should not be boiling. The range to mash is ~148-158°F. And the time period for the mash is important for conversion. True, you may not need an hour if you do an iodine test, but the hour is a safe period to ensure conversion without a test.
 
They also sell "no boil" beer making kits where you just add tap water to hopped extract stir it up and add yeast. Maybe a campden tablet or something to sterilize. So I guess you don't NEED to boil that much, but I sort of feel like the boil is the easiest part of the whole endeavor. After the hot break you can pretty much just sit back and have a beer and toss some hops in every once in a while
 
Yeh, Bobby B has the correct issue.

I usually don't boil the extract wort for more than 20 minutes or so. If I'm preparing a separate mini-mash from grains to be added to the "main" boil, I could save some time if this non-extract wort (e.g., the grain mash) does not have to be boiled for 1 hour.

Yeh, I'm mashing at around 150F only.

Time is $ and I'm trying to reduce kitchen time without cutting corners.

Thx...
 
There are at least a couple things that a long (60 min or more) boil does:

Changes flavor, color, and fermentability through the formation of Maillard products (NOT caramelization - sorry, pet peeve).

Allows SMM (the DMS precursor) to vaporize and be driven out of solution. DMS is the "canned corn" flavor that sometimes can be tasted in beers that don't utilize a long boil, especially with pilsner malt.
 
You doing steeping grains for color and flavor or actual mashing for fermentables?

...for both color/flavor and fermentables. Isn't this question dependant upon how big your grain mash is compared to the extract and which grains you are using? Typically, I'll mash (steep) 2 or 3 lbs of grain for a 5 gallon match but sometimes, less.

..obviously, for the bigger mashes i'll use mostly a pale malt or light grain. If for color only I'll use less than 1 lbs. of specialty grain, for example.

Thx...
 
A mash is a mash regardless of 2 lbs or twenty. It will take 30-60 minutes to fully convert. Without doing an Idodine test to check, you wait 60 to be sure. Now if you're not boiling that portion of the wort, you're not concentrating it therefore your OG will be lower than if you had and like Bobby said, hop utilization will be effected.
 
Is it niave to assume the barley malt extract manufacturor boiled the wort for 1 hour before the water was removed to create DME for sale to home brewers?

I've read many posts that say there is no need to boil DME wort for long periods unless you are trying to mimic a specific hop outcome (e.g, a specific bitter and aroma profile that requires a long boil).

Thx...
 
OK - thanks. I think I have the mash part down. I steep grains in in a bag at 150F in water in a separate pot for about one hour.

My question is really, after the one hour mash has been completed, do I need to boil at 212F the grain mash for one hour or can I just add the grain wort to the extract main boil for 10-15 minutes at the end of the boil?

I guess the short question is: do I need two hours of stove time (1 hour for mashing, 1 hour for boiling) if I am steeping grains that will be added to an extract wort?
 
OK - thanks. I think I have the mash part down. I steep grains in in a bag at 150F in water in a separate pot for about one hour.

My question is really, after the one hour mash has been completed, do I need to boil at 212F the grain mash for one hour or can I just add the grain wort to the extract main boil for 10-15 minutes at the end of the boil?

I guess the short question is: do I need two hours of stove time (1 hour for mashing, 1 hour for boiling) if I am steeping grains that will be added to an extract wort?

You don't need to, but you'll have to figure that in for your expected gravity and adjust your hop profile to compensate. 10-15 is plenty to boil for sanitizing reasons.
 
I've been told there are five main reasons for boiling the wort.

1. Sanitization - This can be done with a reduced boil time
2. Isomerization - This could be done with a reduced boil time, if you use a hop extract.
3. Volitization - The only way I can think of to reduce the time here is by using darker kilned base malts. The darker they're kilned, the more SMM was already converted to DMS and driven off.
4. Concentration - Probably not an issue for you
5. Coagulation of proteins - I'm not totally sure, but I think as long as you boil long enough to get your hot break, you're fine here.
 
I've been told there are five main reasons for boiling the wort.

1. Sanitization - This can be done with a reduced boil time
2. Isomerization - This could be done with a reduced boil time, if you use a hop extract.
3. Volitization - The only way I can think of to reduce the time here is by using darker kilned base malts. The darker they're kilned, the more SMM was already converted to DMS and driven off.
4. Concentration - Probably not an issue for you
5. Coagulation of proteins - I'm not totally sure, but I think as long as you boil long enough to get your hot break, you're fine here.

Great summary. Remember, from 9000BC to the renaissance, beer (or its cousins) was about the only safe thing to drink, primarily due to the fact that it was boiled to kill the microorganisms that make us sick. We take for granted the fact that we can just draw safe water out of the tap, but the concept of sanitized municipal water is very new, and still unknown in many developing worlds (even China).

If you don't boil the wort or at least sanitize it somehow, you will end up with either vinegar or sour beer. Trust me...why don't you leave your spent grains out until the next day. They will smell sour and foul due to the wild yeast and bacteria crawling over the grains.
 
It would take a little software figuring to see how you'd have to change your hop bill but sure, you can accomplish what you're after in about an hour and a half. How big is your boil kettle? One of the benefits to using all mash-derived wort as your starting boil is it can be more volume. You'd have higher extract efficiency. It really depends on how much of the total fermentables you plan to get from the mash. If it's a minor role, it won't matter much. In any case, I'd want to vigorously boil the mash derived wort for at least 20 minutes to get your hot break and boil off the DMS precursors.
 
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