What does it mean to add LME at "knockout"?

[hokenfloken]

I am reading "How to Brew" by John J. Palmer and nearly every recipe calls for the addition of approx. half of the LME at "knockout." Can someone please explain to me what this means and why one would want to add half of the LME later than the rest. By the way, you guys are absolutely amazing! This is the best forum I've ever used. Revvy, you're the best...I don't know how you answer questions as fast as you do but I really appreciate it. I love this site!

 

[flyangler18]

Can someone please explain to me what this means and why one would want to add half of the LME later than the rest.

The knockout addition occurs when the heat is shut off - at 'zero'; there is plenty of heat to dissolve and pasteurize the remaining extract.

The 'why' is a simple matter as well, and is primarily one of color. It is very difficult to keep extract based recipes in style with color because the extract will darken during the boil. Reserving the majority of the extract for a late addition will help keep the color lighter (though extract based recipes are always darker than their AG counterparts). You get enough extract in solution to isomerize the alpha acids in the hops by adding a portion at the beginning of the boil, making up the rest of the gravity with the late addition.

 

[BierMuncher]

+1 to Fly's response.

# one complaint amongst extract brewers is that their light beers are too dark in color.

Easiest fix is to reduce caramelization by not boiling a large portion of the extract...but rather adding at the end of the boil to dissolve.

 

[wilserbrewer]

Just in case you don't know, never add LME w/ any heat on whatsoever or you may scorch the wort.

 

[CATFISHER74]

What about DME?
Do you have to do the same thing?

 

[Thumper]

What about DME?
Do you have to do the same thing?

This technique works just as well with DME. I do with all of my extract batches or PM's.

 

[wilserbrewer]

What about DME?
Do you have to do the same thing?

Good point, not absolutely sure, DME tends to float so perhaps it is less prone to scorching on the bottom of the pot.

Just out of habit, I always would kill the flame during extract additions. Especially w/ LME, that heavy syrup goes directly to the bottom of the pot no matter what.

 

[hokenfloken]

So, there's been all this talk of color. Does adding the last half of the LME at the end of the boil also effect flavor? Here's my situation. I got a Rogue I2PA kit from an ingredients website and it includes 12 lbs of LME. I was thinking of doing the first 6 lbs as I normally would and then doing the other 6 lbs at flameout. Will this have any effect on how the bittering, flavoring or aroma hops brew into my beer? Also, by "flameout" are you referring to the VERY end of the boiling process, right before putting the wort to chill? I'm definitely more interested in flavor issues than color issues, althought a nice golden IPA would definitely be nice.

 

[Yooper]

So, there's been all this talk of color. Does adding the last half of the LME at the end of the boil also effect flavor? Here's my situation. I got a Rogue I2PA kit from an ingredients website and it includes 12 lbs of LME. I was thinking of doing the first 6 lbs as I normally would and then doing the other 6 lbs at flameout. Will this have any effect on how the bittering, flavoring or aroma hops brew into my beer? Also, by "flameout" are you referring to the VERY end of the boiling process, right before putting the wort to chill? I'm definitely more interested in flavor issues than color issues, althought a nice golden IPA would definitely be nice.

Adding half of the extract late actually makes better tasting beer, in my opinion, because there is less boiling of the sugar and less of an "extract-y" taste. If you're doing this with a recipe that normally calls for all the extract at the beginning, you may want to reduce the bittering addition by approximately 25% (or post the recipe, so one of us can help you be more precise about that) because you get better hops utilization in the lower SG wort.

 

[benl560]

i dont know if anyone has asked this before, but wouldn't just boiling the wort from ag or partial mash caramelize the sugar also? when i did a partial method my wort scorched on the bottom of the mash pot while i was sparging before i added any extract. it is a cheap crap pot though.

 

[hokenfloken]

Alright. Here's the recipe I plan to use to make the I2PA:

John Maier's Rogue I2PA

Malt Extracts / Additions: Boil for 60 minutes:
12 lbs Ultralight

Hops:
1 oz Galena (Bittering Hops boiled for 60 minutes)
1.5 oz Cascade (Flavoring Hops boiled the last 30 minutes)
1 oz Sterling (Aroma Hops are boiled the last 15 minutes)
1 oz Sterling (Dry hops added to the secondary fermentation for 10-14 days)

Wort Clarifying Treatment:
Clarifier - Whirlfloc (1/2 - 1 Tablet) - Add last 5 minutes of the boil

Alright. That's the recipe. What hop adjustments should I make if I plan to add 6 lbs of LME at "knockout"? Also, just to clarify, the entire boiling process should only take 60 minutes, right? I just keep on adding the hops and after 60 minutes I'll be done?

Please give me your input. Thanks!

 

[Gremlyn]

Usually you will want to add 1/2 to 2/3 of the extract at the beginning, otherwise you're just boiling hops in water. You add the rest at the end, I usually do it in the last 15 mins of the boil. Never tried it after coming off the heat, might have to next time...

 

[HellenicHomeBrewer]

Will Beersmith adjust hops based on boil size?

 

[Yooper]

Will Beersmith adjust hops based on boil size?

Yes. If you change the boil size (and the time of the extract addition), the IBUs will change in the recipe.

 

[hokenfloken]

Yooperbrew...

Could you give me some insight into what would happen to my posted recipe if I did a half and half of my LME at the end of the recipe? What effect would it have on flavoring and aroma hops? Would it only really effect the bittering hops? What if I used three gallons of water? Thanks. You guys are great! Plenty of fellow Michiganders on here!

 

[Yooper]

Yooperbrew...

Could you give me some insight into what would happen to my posted recipe if I did a half and half of my LME at the end of the recipe? What effect would it have on flavoring and aroma hops? Would it only really effect the bittering hops? What if I used three gallons of water? Thanks. You guys are great! Plenty of fellow Michiganders on here!

It only affects the bittering hops- the flavor and aroma hops will stay the same.

Are you using 12 pounds of DME, or LME? I can calculate it in Brewsmith.

 

[Yooper]

Also, if you can tell us the AAUs (%) of the hops, we can be more accurate.

 

[hokenfloken]

Alright. Here's the specs on the recipe.

I'm using 12 lbs Ultralight LME

I want to use 6 lbs at the start and at 6 lbs at knockout, unless you would recommend a different ratio.

The AAUs for the hops according to the bags go like this:

1 oz Galena (11.8% AAU) Bittering Hops boiled for 60 min.
1.5 oz Cascade (7.5% AAU) Flavoring Hops boiled the last 30 min.
1 oz Sterling (6.0% AAU) Aroma Hops boiled the last 15 min.
1 oz Sterling (6.0% AAU) Dry Hops

I wouldn't mine a bitter, hoppy brew. Does most of the "flavor" come from the bitterness or the aroma? The recipe estimates the IBUs at 60-60.

 

[Yooper]

That recipe will get you around 57 IBUs, if you add half of the extract at the beginning, and half with 15 minutes left in the boil. If you add the second half of the LME at "knockout" (and I would, just so you don't have to bring it back up to a boil for more hops)- you'll have 65 IBUs. That seems perfect for that much malt.

Beer "flavor" comes from all of the ingredients- the malt, the yeast, and the different hops additions. What we think of as the bitterness comes from additions that are boiled for 30 minutes or longer. What we think of as hops flavor comes from the later additions, when the hops are boiled 15-5 minutes at the end. Most of the hoppy aroma comes from flameout additions, and dryhopping.

 

[hokenfloken]

So.... as a side question. I am using Safale US-5 yeast for this Imperial IPA. What are your thoughts on pitching extra yeast when using 12 lbs of LME. For a beer with such a high starting specific gravity, would it be beneficial to pitch extra yeast?

 

[Yooper]

Yes, I would. I would also take a look at mrmalty.com and go to the "pitching calculator" that tells you how much yeast is recommended for each wort.

 

[feedbag]

I get how you don't get as much darkening and the benefits of late extract additions, but what about the hot break? If you had it late you wouldn't have a hot break would you? And all that coagulation wouldn't happen, so how would that affect your beer?

 

[Yooper]

I get how you don't get as much darkening and the benefits of late extract additions, but what about the hot break? If you had it late you wouldn't have a hot break would you? And all that coagulation wouldn't happen, so how would that affect your beer?

You don't really get much of a hot break anyway with LME- it's already been boiled and processed. You should still have the same beer qualities as before, just not as dark and/or "extract-y" tasting.

 

[hokenfloken]

I figured I'd go off topic here for a post in hopes that YooperBrew will respond. Last night I brewed my I2PA. After adding the LME at knockout, my yeast still wasn't ready so I brought it up to a boil and boiled it for 5-10 minutes. This is kind of a theory question for you: What happens if you boil your extract in your wort for too long. I don't think I did boil it for too long, I'm just curious about what might happen. Thanks for the input. Go Redwings!!!!