I'm doing an Epic Pale Ale clone with this partial grain kit. The kit includes two un-hopped liquid malt extract cans. Sterilisation aside, I want some clarification as to whether you should boil un-hopped malt extract.

In Randy Mosher's awesome Radical Brewing book he seems to say you do boil it:

If you're an extract brewer, somebody has done all this work for you, and this is where you take over.

The wort is transferred to a kettle and brought to a boil...

Looking at the Black Rock extract website, their process shows that they already boil when making the extract.

The Beer and Wine Journal says:

Extract brewers should boil the largest volume of wort they can manage, up to a full-wort boil. The more volume you boil, the less color pick up you will get. In addition, the corresponding lower specific gravity will increase your hop utilization.

but then in the very next paragraph:

Brewery grade malt extract has already been boiled. It does not need to be boiled again.

On here user jsled said (see also brewchez's commnent)

You do need to boil the hops in the presence of wort sugars to isomerize the hop oils to get bitterness.

So there seem to be two questions emerging here.

  1. Do you need to boil un-hopped malt extract? Why?
  2. Do you need to boil hops in the wort? Why?

Apart from jsled's comment about isomerization, all the other suggestions about boiling extract seem to be "boil it in as much water as possible" to get around the hop utilisation issues and colour pickup issues. If we get better hop utilisation boiling with lower SG, then the lowest of all will be... water. If we just don't boil the extract at all can't we simply avoid these concerns entirely?

For my two-cents, the best home-brew I ever made was a partial grain IPA where I didn't boil the extract and boiled the hop schedule separately in water. Even my sweet-mouthed malt-loving friends thought it was great. I'm sure Randy would approve as long as it tastes good, but I'm interested in understanding the chemistry.

4 Answers 4


All brewing extracts were boiled wort and achieved a hot break at some point and have been reduced to the extract by a couple methods. Generally like you would thicken a sauce by simmering.

That being said at packaging they should be sanitary. However there was a recall of extracts a couple months ago, that were infected and packages started to swell.

DMS potential is low in extracts because of their pre-boils. So this aids to a shorter boil time.

You should always at least get the extract addition to a good sanitation temp like adding it to a boiling "hop water" like you said you did.

1) It doesn't seem necessary to boil an extract. Sanitation and hop alpha acid extraction aside.

As for me brewing is an event and I love the smell of the malt and hops doing their rolling boil dance.

2) I don't think what takes place in the boil concerning the commingling of wort and hops is fully understood, it's just the way it's been done with good results.

It would be an interesting experiment, doing a SMASH batch like you mentioned and conventionally to compare the effects of a separate hop boil.


As far as I'm aware, there are two kinds of extracts. One, described by your source as "brewery grade", does not need to be boiled, because it was. Other kind does.

"Food grade plants often do not use brew kettles or whirlpool tanks and frequently run wort straight from the lauter tun to buffer tanks to feed the evaporator." - so sadly no, not all were boiled. Also, with homebrewing being bigger market each day, it's only a matter of time when unboiled extracts will be marketed as "brewing" ones and sold a bit cheaper than boiled ones. Lower price = more competitive. Unless some companies are doing this already? Hard to know. I know at least one manufacturer that omits this info on unhopped extracts and advises homebrewers to perform boil.

There are many ways to remove water from wort to create extract. It can be vacuum dried, freeze dried, dried using mixed methods. Probably more. That kinds of drying may fail to do two things:

  • Hot break will, naturally, not occur if drying process is not hot.
  • Freezing (and freeze-drying) will preserve bacteria rather than kill it. Other processes without heating might neither preserve nor kill it.

So if you have this kind of extract, you definitely need to boil it.

As for hops, best utilization in lower gravity is only true to some extent. I can't recall exact chemistry, but in hopped wort hot break is much more visible. That's because some chemicals from hops react with polyphenols and protein from wort. Sure, you can get bitterness without these reaction. At the same time, your result will have different taste and aroma. You may perceive this difference as something positive, it depends on your taste, hop variety and kind of wort, but it will not taste in a way people would expect from given set of ingredients. Not really an issue if it's tasty for you and yours... Unless you are making a clone, or want to send it to a contest.


To the best of my knowledge, you don't have to boil the extract.

I usually do boil the extract anyway. When making a partial recipe I am going to be mashing or steeping some of the grains, and making wort with the extract. I will usually measure off the water I want for the mash and while that's going I'll deal with the extract at more or less the same time. I want that wort to be hot when I combine them. Ideally the extract will boil right before the mash is done. Allowing me to mix them and bring it up to a boil for the hops quickly.


You use a kit that has two tins or bags of extract,one of which is hopped.Or they may both be hopped, it really doesnt matter. You warm up the cans (or plastic bags)and empty into you FV, you then add 1.7 litres of boiling water purely to make the mix start dissolving quicker,as it is already sterile. Most kits come with a secondary bag of hop powder, this is for flavour.If you want a different hop flavour then substitute with the one that you want. Do this after 5 days. You could also 'steep' hops in some of the wort in a separat pan along with any say crystal malt grain, as we hear that this type of grain should not be boiled. Steep in 1.5 ltrs at 175F. for 20 mins, maintain temp? (I have not seen this written anywhere.).Now add to FV through a sieve. Make up to 23lts, cast yeast at 70/75f.

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