Low efficiency with malted corn

[kgranger]

I just brewed a chicha style beer with 55% malted corn, 34% pilsner malt, and 11% torrified wheat, with 7 gal in the kettle pre-boil. Brewing software calculated a pre-boil gravity of 1.044, and a SG of 1.050
This is my first time working with malted corn so this could be a process issue, but my efficiency was much lower than expected. Pre-boil ended up being 1.030, with a SG of 1.035. From what I understand, malted corn shouldn't need a cereal mash, and paired with a base malts enzymes, this should be sufficient. Am I missing something working with the malted corn?

 

[wsmith1625]

I've never used malted corn in a recipe, but just trying to get the conversation started. How did you mill it? I would imagine you would need a few passes each with a smaller gap to get it small enough to convert in a 60 minute mash.

 

[rburrelli]

There is an article in the current issue of Craft Beer and Brewing about corn. It is very common to only get around 60% efficiency unless using enzymes. Even on commercial systems.

 

[hotbeer]

Did you check the extract percentage of your corn malt and see if your recipe builder was showing the same?

Or did you just follow a written recipe by someone else? Typically I'd recommend that written recipes get put in a recipe software and make sure the spec's in the database match the malts and other ingredients based on what the particular maltster list for that batch of malt. Particularly if what they say isn't specific about brand or you can't get the exact same thing.

If you have your recipe builder tuned into your efficiencies, then it will show you if you need to use more or less of something than another person might that gets different efficiencies.

 

[AlexKay]

My understanding (though I am working from memory and so am not certain) is that corn really needs a cereal mash even if it is malted.

 

[day_trippr]

Malted corn does not require cooking before mashing, but it definitely needs a fine enough grind to gelatinize at conventional saccharification temperatures. Otoh, unmalted corn needs to be cooked one way or the other, but then it does not contribute any saccharification enzymes to the mash.

I have yet to find a definitive answer to the question "What is the Lintner rating for malted corn?". Even ChatGPT 3 and 4 choked on it - I had to school 3 on WTF "Lintner" means, ffs. Best that I found that might approach "The Truth" is 40~44, which is borderline self-converting. Adding some barley base malt should take care of that though...

Cheers!

 

[kgranger]

Typically I'd recommend that written recipes get put in a recipe software and make sure the spec's in the database match the malts and other ingredients based on what the particular maltster list for that batch of malt. Particularly if what they say isn't specific about brand or you can't get the exact same thing.

I used Brewer's Friend, they even had the exact brand (Riverbend's Cumberland Corn Malt)

but it definitely needs a fine enough grind to gelatinize at conventional saccharification temperatures

This is probably where I came up short. I had a good amount of pilsner malt in there which should have helped with conversion, but I didn't run the corn through the mill. It came looking crushed, very coarsely though. Wasn't sure if milling finer would cause lautering issues, but I had a ton of rice hulls in there anyways, so I guess it would have been fine.

Beer tastes nice and corny anyways, despite being on the lighter side. I soured half of the batch with a lacto pitch, mixed back in and it is tasting very nice. Will bottle condition with brett later on.

 

[marc1]

See this discussion. If I were to try malted corn, I'd mash in with only corn very hot, then let it cool to regular mash in temps

https://www.homebrewtalk.com/threads/your-favourite-ak-recipe.690263/post-9089578

 

[day_trippr]

The words at that link don't make a lot of sense and in large part were countered by others posts...

Cheers!

 

[wsmith1625]

Why not use flaked corn instead of malted corn? I've used it in several recipes with no drop in efficiency. It doesn't require a cereal mash or milling. It's quite easy to use.