Something I hadn't thought of

[Gilbert Spinning Horse]

The problem I've been having since I started brewing 5 years ago is that I'm consistently low on my mash numbers. Given a 77.4% mash efficiency, Beersmith estimates an SG for my grain typical bill of 1.045.
Every time I brew I'm hitting around 1.035, even when I do an overnight mash and it sits there for 8-10 hours. Furthermore the iodine test shows that all the sugars are converted.
I haven't set up Brewsmith properly I'll admit and the beer tastes how I want it, so I didn't really worry about it.
Anyway, last time I bought ingredients my LHBS was out of both of the cheaper types of pale ale malt so I went with one I haven't used before Chateaux Pale ale.
Putting my ingredients into Brewsmith gave me an estimate of 1.046 and measuring it prior to the boil gave me 1.048. I had to check it several times to make sure it wasn't wrong.
I was quite surprised and hadn't thought that there would be such a difference in the amount of sugars available in different malts.

 

[lumpher]

There really shouldn't be that much of a difference. Do they grind it, or do you take it home and grind it? If they do it, they might have changed their roller settings for a better (or double) grind.

 

[Spartan1979]

While I'm sure there are small differences between brands of malt, I very much doubt that it would make more than a point difference.

 

[Gilbert Spinning Horse]

Yeah, it's only an initial observation based on one brew so something else might be going on.
I do get it ground at the shop so that's another possibility, but my numbers have been consistent for years and its only changing to this brand that that there's been a noticeable jump in sugar.

 

[IslandLizard]

its only changing to this brand that that there's been a noticeable jump in sugar.

It's almost 30% higher!
35 points vs. 45 points.

Maybe this last malt was milled finer, or better? That could help with your efficiency.
Do you always sparge, and how?

Any brands or maltsters associated with the cheaper malt you used to get?
You're not in the U.S., you may very well get grain/malt we never see over here.

Maybe it's just a lower grade small kernel 6-row feed grain that was malted?
Have you seen it unmilled and compared with the Chateau malt (which comes from Belgium)?

 

[madscientist451]

The problem I've been having since I started brewing 5 years ago is that I'm consistently low on my mash numbers.

A few questions and answers may be helpful here:
What are you using to measure your gravity?
What method and equipment are you using to make wort?

 

[kevin58]

Beersmith requires that you create a custom equipment profile. You can also customize your mash profiles. When you do this your estimated numbers will get closer to your actual numbers.

 

[Mark3885]

The op stated that the iodine test showed all starches are converted, so how could the numbers be higher? Mash temperature off, causing unfermentable sugars?

 

[Gilbert Spinning Horse]

Maybe this last malt was milled finer, or better? That could help with your efficiency.
Do you always sparge, and how?

Any brands or maltsters associated with the cheaper malt you used to get?
You're not in the U.S., you may very well get grain/malt we never see over here.

Maybe it's just a lower grade small kernel 6-row feed grain that was malted?
Have you seen it unmilled and compared with the Chateau malt (which comes from Belgium)?

Could be milled differently, I'll ask next time I'm in the shop.

Yeah, the cheap malts are Agraria, a Brazilian brand and Viking from Northern Europe.

No, they're not 6 row feed grain.

ETA - No I don't sparge, full volume mash in a bag.

 

[Gilbert Spinning Horse]

A few questions and answers may be helpful here:
What are you using to measure your gravity?
What method and equipment are you using to make wort?

I use a refractometer to measure gravity, though I have a hydrometer which I used to check the refractometer's accuracy and never again.

I mash in a bag in a cooler. I often do overnight mashes, which was the case with this brew.

None of this has much relevance though.

The op stated that the iodine test showed all starches are converted, so how could the numbers be higher? Mash temperature off, causing unfermentable sugars?

Mash temps are spot on, I have three thermometers.

Beersmith requires that you create a custom equipment profile. You can also customize your mash profiles. When you do this your estimated numbers will get closer to your actual numbers.

Yeah, I know. I did say that it's not set up very well so I'm not actually bothered about the discrepancy itself.

 

[bwible]

Couple things that cause low efficiency
1) dough balls or pockets of grain not stirred in. Malt that doesn’t get wet won’t give up its sugar
2) water chemistry / mash ph

Are you doing anything different with your water? I used to get about 75% efficiency until I started adjusting mash ph with acid malt. Just by adding a couple ounces of acid malt my efficiency went from 75% to almost 82%.

 

[Gilbert Spinning Horse]

Couple things that cause low efficiency
1) dough balls or pockets of grain not stirred in. Malt that doesn’t get wet won’t give up its sugar
2) water chemistry / mash ph

Are you doing anything different with your water? I used to get about 75% efficiency until I started adjusting mash ph with acid malt. Just by adding a couple ounces of acid malt my efficiency went from 75% to almost 82%.

I certainly haven't had problems with dough balls, I'm very careful where that's concerned as I often use 25% oats.
No changes made to water chemistry either.

I've never been bothered by the low efficiency, I'm just surprised by the difference in the SG of this last brew when the only variable changed (to my knowledge) is the type of malt.