Help, looking a fermentable malt extract

[Brendan_W]

Hi all,

I've been partial mashing but thought this question would best bee answered in this forum.

Every time I use an LDME or LLME my FG is always higher than expected. I've looked at the potential reasons for this and I think the fermentability of the extract is a big component.

For my next brew I want to do a big west coast IPA which will need to finish dry. I'm going to be using dextrose to help with this but about half of my fermentables will be malt extract.

Does anyone have any recommendations for the most fermentable malt extract they've found?

Cheers
Brendan

 

[MHB]

Given that you are using a brewing extract - not something made for baking and flogged off cheap to home brewers.
All extract will contain both fermentable and unfermentable fractions, the usual assumption is that a wort solids will be 63% fermentable and 37% unfermentable.
DME contributes pretty much 100% of its mass to extract, LME usually about 80%, the 20% being water so it doesn't add to gravity.
Pretty clearly the more malt extract you add, the more fermentables you will have, and the more residual you will be left at the end of fermentation.

If you are doing partial, depending on how well you do it and your choice of malt the resulting wort should have a similar ratio of fermentables : unfermentables.
Note that if you do your partial hotter (mid 70oC and above), the resulting wort will be less fermentable, cooler (low 60oC's) more fermentable, there are a few other things that will/can affect the fermentability of you wort but temperature is the most important.

As you said dextrose is 100% fermentable, as is Sugar (sucrose), just remember that it's got a water attached to the glucose so only 91% (90.91%) solids and 9% water by weight, Sugar is 100% solids.

That sort of covers the three sources of solids in your beer
If you made a wort out of DME and water and it had a gravity of 1.050, then fermented it down to 1.010 we would say it's apparent degree of fermentation (ADF) or attenuation was (change / start *100) 40/50*100=80%. Note the word apparent, the beer is now a mixture of water, alcohol and unfermented extract, as the alcohol is lighter than water we are getting a bit of a false reading and need to apply a correction to get Real Degree of Attenuation (RDF=0.82*ADF) 80*0.82=65.6%
NB - I was just using 40/50/10 numbers as an example, to show the working.

If you want to control the residuals (FG) in your beer, you will need to work out how fermentable your mini mash is, then calculate how much residual you want, work out how much DME/LME you need to get you there, then add as much dextrose or sugar you want to get to your target alcohol content.

Mark

 

[Bribie G]

When mashing your partial component, mashes below 65 degrees will give a more fermentable wort. Then you can rely on the unfermentables in the extract and crystals to provide the body. If you are using a heap of crystal malts you could also cut them back and substitute a bit of black malt to give colour but less sweetness.

 

[Brendan_W]

Hi Mark and Bribie,

Thanks for the info. I will be mashing low to increase fermentability, however it was my understanding that some of the different brands of extracts varied in their level of fermentability (i.e. Coopers v Muntons v Black Rock)?

Cheers
Brendan

 

[MHB]

No doubt there is some difference, I just did a quick google and couldn't find anything like an up to date list that covers anything other than American options.
I'm sure there is one in either new lager brewing or designing great beer (probably the latter) but its old and fairly American from memory.

You could make up some mini ferments (500mL or so) and measure the various results, if you add some nutrient and use way too much yeast (cheap as 514 would be good) the ferment will be over in a day or two.
Other option being to look up the specifications on each malt, they may or may not tell you what you want to know (often not).

Best option being to go AG - you get total control then!

Mark

 

[Brendan_W]

No doubt there is some difference, I just did a quick google and couldn't find anything like an up to date list that covers anything other than American options.
I'm sure there is one in either new lager brewing or designing great beer (probably the latter) but its old and fairly American from memory.

You could make up some mini ferments (500mL or so) and measure the various results, if you add some nutrient and use way too much yeast (cheap as 514 would be good) the ferment will be over in a day or two.
Other option being to look up the specifications on each malt, they may or may not tell you what you want to know (often not).

Best option being to go AG - you get total control then!

Mark

Cheers Mark, hopefully moving to AG in the not to distant future. In an apartment at the moment which is a bit limiting but enjoying it all the same!

 

[dammag]

I'm sure a Grainfather or an urn would be fine in an apartment

 

[Lionman]

The extract I'm using at the moment is imported by Bintani Australia claims 80% fermentable solids. I bought it in bulk (20KG bag) from my LHBS