Partial Mash technique questions

I am trying to tweak my technique to get the best beer out of my partial mash brews. I am using late addition extract and full boils. Since I am doing this do I need to alter the amount of hops I use from the recipe? I know that conventional thinking is that hops utilization is not affected by wort gravity. The wort will have the sugars from the partial mash so its not like the hops are being boiled is straight water.


I was considering adding the LME at flame out. Is there any reason not to do this? I have read multiple threads that suggest boiling the LME for 15 minutes is necessary to sanitize it. Again conventional thinking on boiling water to purify it says that once it has boiled for 1 minute it is good. A max of 3 minutes at high altitude is all that is necessary.

Unless it is a high OG beer, I add at the start to reduce the chance of burning the LME on the bottom of the kettle. If I need to do a late addition of LME, I put the kettle on the cold garage floor for a bit to reduce the temp of the metal bottom. Efficiency is applied lazieness.... do what you can to reduce work later or cause a head smacking error because you rushed something or overthought it.

Not sure where you're getting this "conventional thinking."

First off, gravity does affect hops utilization - the higher the gravity, the lower the utilization. Most brewing software will estimate considerably higher IBUs if you're doing late addition extract. Like you said, there will be some gravity from the mash, but a lot of partial mash brewers are still getting 50% or more of their gravity from extract, so you should check any recipe with any of the various brewing software platforms out there to make sure the target IBUs are what you are expecting.

As for adding all of the LME at flameout - it's fine if that's what you want to do, I'm just not sure why anyone would want to do that. Late addition extract is really about preserving color by preventing caramelization of extract in your boiling wort. Somehow, people have started attributing flavor changes to late addition extract, and, as far as I can tell, there is no evidence that adding your extract later in the boil has any bearing whatsoever on the quality of your beer. You don't need to boil extract at all - it's boiled when it's made, so it's already sterile enough. But, at the end of the day, you want to make sure it's completely dissolved and you want to make sure that your gravity is high enough that you don't get astringent flavors from your hops and you don't want to have to fiddle with trying to figure out how much the late addition is going to affect your hops, so I say just toss it all in at the beginning and boil the darn stuff.

Hop utilization not changed by work gravity discussed here

http://thebrewingnetwork.com/shows/719

TTB-J said:

Not sure where you're getting this "conventional thinking."

First off, gravity does affect hops utilization - the higher the gravity, the lower the utilization. Most brewing software will estimate considerably higher IBUs if you're doing late addition extract. Like you said, there will be some gravity from the mash, but a lot of partial mash brewers are still getting 50% or more of their gravity from extract, so you should check any recipe with any of the various brewing software platforms out there to make sure the target IBUs are what you are expecting.

Click to expand...

There's an episode of Brew Strong where John Palmer talks about hop utilization and refers to recent study that showed that boil gravity does not affect hop utilization.

Also, there are two formulas for calculating IBUs. You should use the same one every time.

I don't know how much of an advantage there is to adding the LME at 15 minutes vs. 0 minutes, as I would think that adding the LME to boiling wort would certainly be enough to pasteurize it. But I think some brewers just want to make sure so add it at 15 minutes. I'd be more likely to add it at flame out, as it would certainly stay above 160 for at least a few minutes to pasteurize.

I would just follow the hopping schedule in the AG batch recipe, if you have that.

silvery37 said:

Hop utilization not changed by work gravity discussed here

http://thebrewingnetwork.com/shows/719

Click to expand...

Correct. John Palmer says he "got it wrong" in How to Brew. But when I pressed him, he acknowledged that there may be a difference in IBUs, but contributed to break material instead of wort gravity. Either way, I wouldn't worry about it except in the lowest IBU beers.

What I mean is, you won't notice the difference between 45 and 52 IBUs even IF it did occur. But you would certainly notice the difference between 16 and 25 IBUs in a light beer. So in a very light beer with low IBUs, I'd be inclined to error on the side of caution and consider reducing the bittering hops by 20% in a full boil vs a partial boil recipe if I was worried about it. That would be the only case I can think of where I"d adjust the bittering hops though.

I will definitely look at the all grain hop schedule. I found a good article on LME. Basically it says that LME should not have any contaminants as it comes from the factory and anything that might get in it would be killed by the water temperature (above 160) even after the burner has been turned off. I was asking because I tried adding the extract with 15 minutes left and it was kind of pain to get the boil going again. It wasnt that hard but it would be easier just to dump it at the end. There is no risk of scorching either.


http://***********/stories/techniques/article/indices/30-extract-brewing/1106-making-malt-extract

It depends on how much you're adding. If you're adding a lot, the LME will absorb a lot of the heat. I usually add extract late for color reasons right after I drop in the chiller while the heat is still on.