Does the boil intensity matter?

[J2W2]

Hi,

When I started brewing, I had a 5-gallon pot on our electric stove,and it was all I could do to get a boil going.

Now I have a 10-gallon kettle and a natural gas burner, so I can get anything from a light boil (like I had on the stove) to a very active rolling boil.

I was just reading an article on things that can cause off taste in beer,and one was long boil times. That got me wondering if the boil intensity has an effect as well.

I brew partial mash kits, and the last couple of batches I've started with 6.5 gallons of water and done a pretty hard boil, getting down to a little over 5 gallons. It seems like the beer is coming out little darker than usual. It's too soon to tell if there is any effect on the taste.

So, I'd like your input on if the intensity of the boil matters, and if so, what level is the best way to go?

Thanks for your help!

 

[IslandLizard]

From what I understand a rolling boil is necessary, but it doesn't need to be overly wild with surges splashing out the top. Vigorous enough, to get the whole volume at roughly the same temps, around 212F (at sea level), you can measure that. Since the top and sides of the wort are heated by hot wort from the bottom, turn over is needed to do that. It also causes boil-off driving off nasty byproducts, like DMS. Depending on your system, 10% boil off per hour seems to be a good starting point.

 

[J2W2]

From what I understand a rolling boil is necessary, but it doesn't need to be overly wild with surges splashing out the top. Vigorous enough, to get the whole volume at roughly the same temps, around 212F (at sea level), you can measure that. Since the top and sides of the wort are heated by hot wort from the bottom, turn over is needed to do that. It also causes boil-off driving off nasty byproducts, like DMS. Depending on your system, 10% boil off per hour seems to be a good starting point.

My kettle is large enough that splashes over the top aren't an issue, but I can definitely get a very rapid boil - well past what I'd call just a rolling boil.

If I start with 6.5 gallons of water, maybe get to 7 with LME addition, and then boil down to 5.25-5.5 gallons in a hour, that's around a 20% per hour boil off. It sounds like that may be too high? Perhaps I should reduce my initial volume down to 6 gallons of water and back the burner down some?

Thanks!

 

[IslandLizard]

I boil 7 gallons (8 gallon pot) and have a gallon boil off per hour, sometimes more. Boil off depends on many factors, kettle size, surface area, temps, air pressure, humidity, air currents, energy supplied, energy transfer efficiency, etc.

So that puts me around 15%.
If I had a kettle that's 2x as tall, same width, the boil off would still be the same gallon (or even less), putting it at 7.5%.

I was afraid to throw a solid number out in the open (i.e., 1 gallon/hr), as it should be relative to your boil volume. 10% maybe a low number. Brew365 has that plugged in by default, among some other "fixed" variables.

 

[IslandLizard]

On a second note, are you adding all your LME/extract at the beginning of the boil? That could cause excessive caramelization and wort darkening. Better to add only a third to half, and the rest at flameout.

Anything past a solid rolling boil is wasting energy in my opinion, and while some of that extra energy supplied to the system adds to excessive boil off, most of it heats up your brew house or your neighborhood.

So yes, I would back down a bit and monitor your boil off a bit closer over an hour's period, like every 15 minutes.

 

[J2W2]

On a second note, are you adding all your LME/extract at the beginning of the boil? That could cause excessive caramelization and wort darkening. Better to add only a third to half, and the rest at flameout.

Yes, I add the DME/LME at the start of the boil. That's what my recipes have always called for. I may have to play around with that as well.

Thanks again for your help!

 

[IslandLizard]

Yes, I add the DME/LME at the start of the boil. That's what my recipes have always called for. I may have to play around with that as well.

Thanks again for your help!

YVW.

Most recipes are outdated on process or imprecise at best. Copied from year to year, without review or revision. Chances are, it still mentions racking to secondary after x days (not even xx days!). Again, mostly unnecessary, and another major cause of problems, and threads here. Racking is NOT a beginners technique. It's seemingly very easy to do but fairly difficult to do it right and at the right moment. You need to know when your beer is done or done enough.

Read around here on HBT, BYO or any other active homebrew website and you'll learn modern takes on age-old methods. That doesn't mean everyone's process is even remotely the same, if that were true we wouldn't have these forums.

As long as you're willing to accept more modern brewing methods developed by homebrewers, many outlined here and elsewhere, and be critical what to adopt and adapt to your own brewing, you can make any beer and likely better than from the "box," basically disregarding the recipe that came with the kit. Soon you'll start thinking of buying your own ingredients for the awesome recipes posted here.

 

[Arrheinous]

I boil 7 gallons (8 gallon pot) and have a gallon boil off per hour, sometimes more. Boil off depends on many factors, kettle size, surface area, temps, air pressure, humidity, air currents, energy supplied, energy transfer efficiency, etc.

So that puts me around 15%.
If I had a kettle that's 2x as tall, same width, the boil off would still be the same gallon (or even less), putting it at 7.5%.

I was afraid to throw a solid number out in the open (i.e., 1 gallon/hr), as it should be relative to your boil volume. 10% maybe a low number. Brew365 has that plugged in by default, among some other "fixed" variables.

Width seems to be a key factor.

I used to get 1 gal/hr with a 6.5G boil using a 15G Bayou Classic with a 15.6" diameter.

Since then I swapped to a 20G stock pot with 19" diameter. That's a 50% increase in area. Now it's more like 2 gal/hr (needing 7.5G preboil to hit 5.5).

Height doesn't seem to be an issue in my experience - I use the volume at 30 minutes of boiling to predict the 60 minute post-boil volume and add third runnings to hit the proper volume. This rate doesn't appear to speed up by 45 - 50 minutes. Also, it seems like the boil-off rate is mostly independent of volume (whether it's a 2G, 5G, or 10G batch) for me.

Humidity can have a pretty big effect too - sometimes 2.5 - 3 G/hr is possible if it's winter and bone dry outside. This weekend I got 1.5G/hr due to a rainy day.

The old kettle was SS and the new one is aluminum. But that probably has more of an effect on how easy it is to reach a boil than boil-off as long as you can achieve the same boil.

A good boil vs. a poor boil should have an effect. If you can only get a hearty boil under some of these conditions then it becomes a lot harder to predict what will happen on the fly. I use an SQ14 propane burner and it made a big impact over stovetop boiling.

 

[beersk]

I get around a 9% boil off rate, while it's not as high as I'd like, it seems to be fine. I use a pretty tall kettle though, so that'd be why. I think as long as the surface of the boil is moving, it's fine. It doesn't have to be jumping or anything, just moderate vigorous or rolling. Mine tends to chill for a second, then boil hard for a second. It's because I'm boiling on an electric stove top that turns the burner on and off to maintain heat levels. But I prefer brewing inside to outside. More consistent boil off, no wind, no bugs, and consistent climate to brew in. Plus I don't have to buy propane.

 

[J2W2]

Ok, after reading the replies in this post, and other related posts, I have two items to work on for my next beer.

First, I'm going to reduce my starting volume to 6 gallons and back off the heat on my boil. Based on what I've read, I'm taking it beyond just a good rolling boil. I'll tweak that starting volume if need be, but I always keep a gallon of boiled water on hand to top off the fermenter if I come up a little short.

Second, I'm going to hold off on adding any DME or LME until late in the boil. I do have a couple of questions about that:

1. A lot of what I've read suggests adding the malt extract around the last 10 minutes of the boil. I've also seen mention of adding half at the start of the boil and the rest in the last 10 minutes. Is there really an advantage one way or the other? What about if I'm brewing a pure extract kit (no specialty grains), does that change when to add the extract?

2. I add rehydrated Irish Moss during the last fifteen minutes of the boil. Would I need to change that if I add malt extract during the last 10 minutes?

Thanks for the help!

 

[Yooper]

Ok, after reading the replies in this post, and other related posts, I have two items to work on for my next beer.

First, I'm going to reduce my starting volume to 6 gallons and back off the heat on my boil. Based on what I've read, I'm taking it beyond just a good rolling boil. I'll tweak that starting volume if need be, but I always keep a gallon of boiled water on hand to top off the fermenter if I come up a little short.

Second, I'm going to hold off on adding any DME or LME until late in the boil. I do have a couple of questions about that:

1. A lot of what I've read suggests adding the malt extract around the last 10 minutes of the boil. I've also seen mention of adding half at the start of the boil and the rest in the last 10 minutes. Is there really an advantage one way or the other? What about if I'm brewing a pure extract kit (no specialty grains), does that change when to add the extract?

2. I add rehydrated Irish Moss during the last fifteen minutes of the boil. Would I need to change that if I add malt extract during the last 10 minutes?

Thanks for the help!

Unless there is a problem, my preference is more of a hard boil than a softly roiling boil. I boil off nearly 2 gallons/hour in my relatively dry climate. That's ok, and my beer is nice and clear as a result due to the great hot break I get.

1. I'd go even further- and add half (or more) at flame out. That way you don't kill your boil at ten minutes and have to bring it back to a boil. Flame out wort is plenty hot enough to pasteurize the extract. The hops do need to boil- so you only need to boil as long as your longest hops addition. Most are 60 minutes, but I have some 'hopbursted recipes' where the first hops are added at 15 minutes from the end of the boil. Since that's as long as you need (extract doesn't need to boil at all), a 15 minute boil in that case is fine.

The biggest advantage is flavor-wise. No "cooked extract" taste, and no excessive maillard reactions (similiar to caramelization type of reaction in the boil).

A decent rule of thumb is to use a pound or less of extract per gallon of liquid boiled. So, if you're starting with a 6.5 gallon boil, you can use up to 6 gallons of extract or less (assuming you have a few specialty grains in there) but it's not like that is written in stone or anything. More, or less (alot less!) is fine.


2. I have no idea, but you can wait to you bring it back to a boil and then add the Irish moss, no? The extract WILL stop the boil if you add it at 10 minutes, which can also screw with your hops additions in beers that have late hops so this would not be my preference at all.

 

[J2W2]

Unless there is a problem, my preference is more of a hard boil than a softly roiling boil. I boil off nearly 2 gallons/hour in my relatively dry climate. That's ok, and my beer is nice and clear as a result due to the great hot break I get.

1. I'd go even further- and add half (or more) at flame out. That way you don't kill your boil at ten minutes and have to bring it back to a boil. Flame out wort is plenty hot enough to pasteurize the extract. The hops do need to boil- so you only need to boil as long as your longest hops addition. Most are 60 minutes, but I have some 'hopbursted recipes' where the first hops are added at 15 minutes from the end of the boil. Since that's as long as you need (extract doesn't need to boil at all), a 15 minute boil in that case is fine.

The biggest advantage is flavor-wise. No "cooked extract" taste, and no excessive maillard reactions (similiar to caramelization type of reaction in the boil).

A decent rule of thumb is to use a pound or less of extract per gallon of liquid boiled. So, if you're starting with a 6.5 gallon boil, you can use up to 6 gallons of extract or less (assuming you have a few specialty grains in there) but it's not like that is written in stone or anything. More, or less (alot less!) is fine.


2. I have no idea, but you can wait to you bring it back to a boil and then add the Irish moss, no? The extract WILL stop the boil if you add it at 10 minutes, which can also screw with your hops additions in beers that have late hops so this would not be my preference at all.

I'll stick with 6.5 gallons of water,and stay with a harder boil.

You said to add half or more extract at flame out. Is there a benefit to adding some earlier? If not, why add any early, or does that make the color too light?

As far as the Irish moss goes, does extract really add any particulates to the wort? I assume it would be little to none since it's already been processed.

Thanks!

 

[Yooper]

I'll stick with 6.5 gallons of water,and stay with a harder boil.

You said to add half or more extract at flame out. Is there a benefit to adding some earlier? If not, why add any early, or does that make the color too light?

As far as the Irish moss goes, does extract really add any particulates to the wort? I assume it would be little to none since it's already been processed.

Thanks!

It would be easier to dissolve if you use some in the beginning, plus the hops get harshly bitter when boiled in just water. I forget the details of the science behind that, though! Some extract, or some runnings from a partial mash, impact the hops isomerization and flavor so using some at the beginning is recommended.

I see plenty of chill haze in extract beers, so yes, I think that Irish moss (or whirlfloc) does help coagulate proteins and prevent chill haze in extract beers.

 

[J2W2]

Thank you very much for your time and detailed information; I'll have several new things to try on my next brew - hopefully next weekend.

 

[shortyz]

i add all my extract at flameout, i am brewing partial mash. I found that adding extract at the boil gives a weird flavor to the beer.

 

[jimbobbillyray]

Unless there is a problem, my preference is more of a hard boil than a softly roiling boil. I boil off nearly 2 gallons/hour in my relatively dry climate. That's ok, and my beer is nice and clear as a result due to the great hot break I get.

1. I'd go even further- and add half (or more) at flame out. That way you don't kill your boil at ten minutes and have to bring it back to a boil. Flame out wort is plenty hot enough to pasteurize the extract. The hops do need to boil- so you only need to boil as long as your longest hops addition. Most are 60 minutes, but I have some 'hopbursted recipes' where the first hops are added at 15 minutes from the end of the boil. Since that's as long as you need (extract doesn't need to boil at all), a 15 minute boil in that case is fine.

The biggest advantage is flavor-wise. No "cooked extract" taste, and no excessive maillard reactions (similiar to caramelization type of reaction in the boil).

A decent rule of thumb is to use a pound or less of extract per gallon of liquid boiled. So, if you're starting with a 6.5 gallon boil, you can use up to 6 gallons of extract or less (assuming you have a few specialty grains in there) but it's not like that is written in stone or anything. More, or less (alot less!) is fine.


2. I have no idea, but you can wait to you bring it back to a boil and then add the Irish moss, no? The extract WILL stop the boil if you add it at 10 minutes, which can also screw with your hops additions in beers that have late hops so this would not be my preference at all.

Is that rule of thumb for DME and how would one figure If using LME (since it has water it's weight is more than malt unlike LME I think???)

 

[Yooper]

Is that rule of thumb for DME and how would one figure If using LME (since it has water it's weight is more than malt unlike LME I think???)

It wouldn't matter, it's a 'more or less' kind of thing. It just means that there is some extract in there, and it's not an exact thing. Many people go with much less, some go with more.

 

[jimbobbillyray]

Thank you!!!