Potential Extract

[jamesb]

Hi All.

I''m confortable with calculating efficiences, etc using our normal system. What I'm trying to figure out now is the extract of certain grains to fit into third party software. This may also answer other people's questions at some point.

QBrew specifies it's extract potential for Maris Otter as 1.038 - that's the potential extract of 1lb of grain in 1 gallon (Ha - US gallons, that got me for a bit), whereas on the correct side of the pond we express it as a potential extract of 300, which is the potential extract of 1kg of grain in 1 litre of water.

So, to convert our system to theirs,

300 / 3.78 = 79.365 (to convert to extract for 1 us gallon)

79.365 / 2.2 = 36 (to convert to pounds)

So by my calculations, the potential extract of MO the US way is 1.036 - a discrepency of .002 from the figure normally quoted by QBrew and sites on the Interweb.

If I convert the US PE of 1.038 back to the uk way, I get a potential extract of 316, which seems a lot.

The MO I've come across has always varied between 295 and 305. Does anyone know why I'm getting such a high discrepency here? I don't know if they grow Maris Otter in the US, but would it have a higher extract potential?

 

[EskiBrew]

The MO I've come across has always varied between 295 and 305. Does anyone know why I'm getting such a high discrepency here? I don't know if they grow Maris Otter in the US, but would it have a higher extract potential?

A lot of things affect the potential of any grain from season to season therefore the only accurate figure to use is the one that the maltster supplies with the grain when you buy it. If you happen buy grain from HB shops then who knows what potential it has

This caused me some consternation when putting together the recipe creation tool/database because someone entering a recipe on our system may well come up with different OG expectations than when they enter it on their own computer program because they are using different figures for potential to the ones we are using. I intend making a change to the recipe tool so that if people want to, they can specify their own potential figure or they can use our default one.
Our figures are based on average figures achieved over a number of years.

As for whether they grow MO outside the UK... From my rather poor memory of a lecture at the Derby Craft Brewing festival the other year, there are reported cases of the seed grain being taken out of the country so it can be grown elsewhere however the MO seed owners do not sell it for growing outside of the UK and there are very tight laws regarding what can and cannot be called MO (sort of like copyright but for grain). The short answer is that what is called MO when sold is ONLY grown in the UK :thumb:

 

[jamesb]

Good to know it's not me just being daft and the yanks are overoptimistic

Cheers EB!

 

[Aleman]

Another factor is whether you are talking dry basis or not? Which can account for 3% (IIRC) . . . and then if the grain is poorly stored the moisture content can be higher . . . Lower extract potential . . .

 

[Vossy1]

When you get your analysis figures for the malt, the best figure to use is the tested 'as is' figure, for the reason's Aleman has said.

 

[jamesb]

Yes, I was going to bring that up this morning.

The figures I have (for one batch) from Warminster

Maris Otter:
As is - 302
Dry - 314

Lager Malt:
As is - 303
Dry - 315

It made sense to me to use the "As is" figure due to the inherent moisture that would be present.

Ok, next question.

Colour - 5.5 or 4.6 using the Pre-2008 calculation.

Anyone know what this difference in calculation is?

 

[Aleman]

Ok, next question.

Colour - 5.5 or 4.6 using the Pre-2008 calculation.

Anyone know what this difference in calculation is?

No . . . Then there is the ISBC or the EBC calculation anyway . . . And then calculating beer colour via the Daniels, Mosher, Morey et al methods. . .

 

[jamesb]

Ok, next question.

Colour - 5.5 or 4.6 using the Pre-2008 calculation.

Anyone know what this difference in calculation is?

No . . . Then there is the ISBC or the EBC calculation anyway . . . And then calculating beer colour via the Daniels, Mosher, Morey et al methods. . .

Heh. Never mind, I'm not interested in calculating colour for what I'm up to. Just curious.