Different OG's using US to UK Software

[Big G]

Hi Gents

I have been having a few issues with OG readings using Beersmith and Promash compared with Beer Engine.

I brewed this Beer on the weekend

4.80 kg Pale Malt, Maris Otter (5.9 EBC) Grain 68.57 %
1.00 kg Barley, Flaked (3.3 EBC) Grain 14.29 %
0.50 kg Oats, Malted (2.0 EBC) Grain 7.14 %
0.35 kg Black (Patent) Malt (985.0 EBC) Grain 5.00 %
0.35 kg Roasted Barley (591.0 EBC) Grain 5.00 %

Beersmith & Promash gave me an estimate of 1.063 @75% Efficiency
Beer Engine gave me an estimate of 1.055 @75% Efficiency

My actual OG was 1.055!!!! Can anyone shed any light on this?

[Blackaddler]

Are you adjusting for Imperial gallons, rather than US gallons?

[boingy]

Are you adjusting for Imperial gallons, rather than US gallons?

That would be my best guess too.

Failing that, it's possible that the programs have different "extract potentials" in their grain databases, although they would have to be very different to account for the discrepancy.

[Big G]

I have changed the defaults to Litres, is that what you mean?

[Blackaddler]

I use a modified version of SUDS spreadsheet, which I've found to be quite accurate.

Using the above figures for [presumably] a 23L brewlength, I get OG1.068 at 75% efficiency.

[Big G]

I think my efficiency is more like 65% DOH!

[Blackaddler]

At 1.055, that would be about 61% efficiency, which seems rather low.

Something doesn't sound quite right to me.

[boingy]

Just check your brew length.
What did you use in the recipe and what volume did you end up with?

[Big G]

I used 39L and ended up with 24L. For some reason this stout recipe always falls well short of OG on previous attempts. I hav'nt had this problem on other styles.

Could the large amount of Flaked Barley & Oat have an effect on efficiency?

Oh I made a mistake on Beer engine.....I only put 35g of Black & 35g of Roast Barley in, should be 350g each which turns out at 1.060, double doh!

[gregorach]

Low efficiency in a stout could well be down to incorrect mash pH - the high proportion of dark roasted grains needs more alkalinity to keep the pH in the right range.

[Big G]

Low efficiency in a stout could well be down to incorrect mash pH - the high proportion of dark roasted grains needs more alkalinity to keep the pH in the right range.

Treated Liquor PH was 7.1 & Mash PH was 5.2

[gregorach]

Well, it's not that then...

[Big G]

Another confusion is that it tells me I will FG @ 1.016 but I bet my bottom dollar it will finish at 1.010/1.012 as I usually do, so I guess I will grab a few ABV's back!

[boingy]

So if the pH was OK and the grain was OK (Is it fresh and crushed right?) then it has to be either temperature control across the mash or a sparging problem.

[Big G]

So if the pH was OK and the grain was OK (Is it fresh and crushed right?) then it has to be either temperature control across the mash or a sparging problem.

The only thing I can think of is my Fly Sparging method, I manual fly sparge for around 20-30mins with a fine spray action from a crimped end copper nipple attached to my hose. I find this method VERY anoying as it takes up 30mins of me waving this sprinkler around where I could be doing other stuff! Thinking about it, its the only variable that is in my brewing.

I am in the process of building my own rotating sparge arm, I have just managed to find a rotating joint that proved a royal pain in the arse to find!