Effects of high crystal percentage in grain bill

[TomVA]

I recently brewed a few dark London style ales with Maris Otter base but used a very high percentage of crystals, like 22% total of such as crystals as 90L and Special B. Overall the ales taste good but there is a taste in them that I can't describe - best I can come up with is metallic fruit, but that is so subjective. I have enough wine tasting experience to know it is not oxidation or tannins, and I am very careful about sanitation and process control. These ales were mashed at fairly high temperatures of 156 to 160°F, fermented for 3-4 weeks with S-04 at an ambient temperature in the low 60s, and only contacted stainless steel pots and plastic pails.

Since I can't describe the taste or expect anyone to guess from such limited information, I thought I would ask the question from a different point of view:

How would you describe any off-flavors would you expect to find in an ale brewed with excessive crystal malts?

Thanks!

Tom

PS - I plan to brew a new batch tomorrow with half the crystals, 8% 60L and 3% chocolate.

 

[kh54s10]

Lots of Crystals = a lot of unfermentable sugars. 156-160 degree mash - more unfermentable sugars. S-04 is not as clean fermenting a yeast as others so - more unfermentable sugars. I would expect a very sweet beer. Not sure about other off flavors. Fruit flavor could be the sweetness combined with the hop flavors. Metallic is more of a problem.

 

[BigEd]

PS - I plan to brew a new batch tomorrow with half the crystals, 8% 60L and 3% chocolate.

I suspect you will notice a big improvement in the beer. Crystal malts should be used for accenting flavor and color. As kh54s10 said crystal malts have a low percentage of fermentable sugar compared to base grains. Too much crystal is going to lead to an overly sweet and "flabby" final product. Crystal malt @ 5% will usually get the job done although in certain cases up to 10% or maybe 15% in the extreme will yield a good beer depending on factors such as other ingredients in the grain bill, mashing schedule, and yeast/fermentation. The 22% in your original recipe is just way too much.

 

[TomVA]

I was shooting for a London Brown Ale style with a full body, low alcohol (3.5-4.0%) and a touch of sweetness. I understand S-04 is a relatively low attenuator, however I would think that 15-20 days at ambient 62°F followed by a rousing and another week+ at 71°F should allow it to eat pretty much all sweet sugars. I'm not sure but I don't think sweetness is what I am tasting.

Tom

 

[Calder]

Out of interest, what was the OG and FG?

22% is high. I try and minimize crystal, if not avoid it altogether in some beers. Crystal has a lot of complex sugars which are not broken down by the mash, and are not converted by most regular ale yeasts. Addition of crystal will increase the FG, and the more crystal, the higher the FG (= sweeter beer).

 

[TomVA]

Out of interest, what was the OG and FG?

The most recent batches had an OG of 1.051 and an FG of 1.021. An earlier batch was OG 1.043 and FG 1.019.

 

[Sadu]

Those FGs are pretty high. For a 1.051 beer, you would generally find those to finish in the 1.008-1.015 range, depending on style of course. I don't like the flavours associated with too much crystal and generally try to minimise its use.

 

[nmenninga]

Old malt gives metallic flavors. Crystal gets made in large batches, then used in small amounts. Likely the stuff you used has been sitting somewhere for a long time between malt day and brew day.

Just a thought.

High proportions of crystal/caramel tends to give me a sickly sweet malt flavor, impossible to balance against hops. I've never taken it to 22%, I would predict: something yucky is likely, let's call it a flavor short-circuit. Anything can happen there.

Special B can help impart stone fruit flavors, to my pallet. Another thought.

 

[BreezyBrew]

With a metallic flavor, I'd look at mash pH.

 

[Hookstrat]

Kudos! There is nothing wrong with using that much specialty malt, but I think easier to pull off in a bigger beer capable of aging for 1+ years. Note, for example, if you look around at Hunahpu clone recipes (https://www.homebrewtalk.com/showthread.php?t=406876) it's common to have the specialty grain bill exceeding 20%. Granted that is layering different types of crystal and roasted grain, but point is that the quoted max percentages are just a guideline.

The highest I've ever gone is 27% Briess Extra Special Malt in a Belgian Dark Strong secondaried w Brett. Happened because I accidentally ordered 4#s instead of 4oz and wanted to experiment. It was a delicious mistake!

 

[mjbennett]

If you want to add body without adding a whole lot of sweetness, add a dextrin malt to the mix. Or, just go with maltodextrin powder.