Need help with consistent 'grainy' off-flavor

[csdunham]

I have been all-grain brewing/BIAB brewing 1 gallon batches for a year now. Each batch I improve my process and each batch has been better than the last. However there is one off-flavor that has been in all of my beers that I can't get rid of. The best way I can describe it is a grainy after taste.

I use a corona mill to crush my grain and I have read that excessive shredding of the husks can lead to this flavor. However I do not know if my crush has 'excessive' shredding in it. I have attached a picture of several crushes from my mill. The crush on the left is what I have been using. The crushes on the right are my fiddling with the mill trying to reduce the shredding. But I think there is too many whole grains remaining in those crushes.

I have also read that sparging with water that is too hot can lead to extracting tannins from the husks. I wouldn't describe the off-flavor as 'astringent' but perhaps I don't have a good idea of what that tastes like.

My current process is to pull the bag out of my mash pot, let it drain, then dunk it into a second pot of water that has been brought to a boil and then cooled for 10 minutes. The volume of water is equal to what I need to add to my mash pot to reach my boil volume. While in the sparge pot I stir the hell out of the grain for several minutes and lift the bag and it let it drain again. Could the off-flavor come from sparging too hot or from stirring the grains?

 

[billl]

If you boil the water and let it cool for only 10 minutes, that is probably too hot for a sparge. With small batches, the boiloff is a much larger portion of the total volume, so ph is often higher than larger batches. Higher ph + higher temp is a formula for grainy off flavors

 

[Brettomomyces]

I agree, I would verify the temp with a thermometer next batch and you will most likely find it's too hot. I'd shoot for 175F for the dunking step...no need to bring it up to a boil first either.

 

[csdunham]

Can you elaborate on why the pH is higher? Wouldn't the pH be the same during the mash/sparge since the ratios of grain/water are the same despite batch size?

 

[chickypad]

It's not your crush, BIAB'ers crush a lot finer than that one on the left and the ones on the right look almost uncrushed to me. Why are you boiling your sparge water? With batch sparging you can use room temp water if you want, though it will take longer overall to get your boil going. I certainly wouldn't boil for 10 minutes. As mentioned it's high pH + high temp that puts you at risk for tannins. What do you know about your water and are you treating it in any way?

Edit: I see you are boiling for 10 but cooling that long, still no need to let it get that hot at all. I aim for around 150-160 (when I remember to heat the sparge water in advance).

 

[cubalz]

I heat my sparge water to between 170 – 180 degrees. Never an issue with off flavors ever.

 

[dmtaylor]

The high temperature thing is most likely a myth.

However, the mash pH thing is very real. What is your water source? How do you treat your mash and sparge water? What is your mash and sparge pH? If you can't answer these questions, then this is most likely your problem. You want to shoot for about 5.2 to 5.5, with an ideal of 5.3. If it's 5.6 or 5.8 or something like that, you've got a problem. Solution is simple -- use a few drops of lactic acid, or add 1% acidulated malt per 0.1 pH that you need to reduce to get into range (typically like 2-4% for hard alkaline water).

 

[csdunham]

I use grocery store spring water in 1 gallon jugs. I have not gotten into checking the mash pH but perhaps i should.

 

[Bellybuster]

I don't even heat sparge water for BIAB, takes a few minutes longer to come to boil but then I don't need a separate vessel for heating sparge water. Win
I also only sparge if I need more volume than my pot can handle with the grain in. Full volume mashes are like no brain brewing.

 

[billl]

Can you elaborate on why the pH is higher? Wouldn't the pH be the same during the mash/sparge since the ratios of grain/water are the same despite batch size?

You need more water in either the mash or the sparge to make up the volume. If you keep the mash constant, then you are sparging with more water. Depending on your water and grain bill, the ph could certainly get up higher than you would like.

 

[chickypad]

I use grocery store spring water in 1 gallon jugs. I have not gotten into checking the mash pH but perhaps i should.

If you're having off flavors you definitely should. Many bottled waters have bicarbonate added, if you are not adding any acids you could very well have too high a pH. Even with my tap water which is essentially RO I have to add a little acid on the pale grainbills. At the least I would suggest using RO water instead of spring water and following the directions in the water primer.

 

[dmtaylor]

I use grocery store spring water in 1 gallon jugs. I have not gotten into checking the mash pH but perhaps i should.

Spring water = generally BAD. Very hard, "flavorful" water that is generally NOT good for brewing. If you're going to buy your water, you would be much better off buying distilled water and adding your own salts. Yep... pH is your problem. Check your mash pH with spring water next time. I bet it's too high, unless maybe you're brewing a really dark beer with lots of specialty malts, then you might be alright.

 

[csdunham]

Thanks everybody. I'm going to rebrew the exact same recipe with a water profile made from distilled water. Then taste the two beers side by side.

 

[Tippsy-Turvy]

The high temperature thing is most likely a myth.
However, the mash pH thing is very real.

I'd agree. My boiling hot decoction mashes don't produce any astringency.

Getting a ph meter should be high on your Christmas shopping list. In the meantime, reduce your sparge water volume to produce a thick sparge. That way, your sparge ph won't be as high. But keep the sparge temperature high (~170F) as the whole point of the dunk sparge is to dissolve as much remaining sugar as possible.

AFTER combining the worts in the pot, then top up with more water to reach your targeted boil volume.

 

[PeteNMA]

You can get a pH meter on Amazon for less than 20 bucks. I've got one and it works just fine.

Do be aware that the pH will vary according to temperature. You are shooting for pH 5.2-5.5 at mash temps, but you should actually pull a sample of the mash, cool to room temp then measure. pH at room temp will be about 0.3 higher, so you are aiming for about 5.5-5.8 at room temp.

 

[TheMadKing]

I have had this same off flavor in all my lighter beers! I do BIAB/no sparge so I don't think tannins or sparge temp are your problem. It could be a mineral addition or pH issue. I usually do 50/50 RO water and tap water with some mineral and acid additions. I use Bru'n Water for all my adjustment calculations.

I have been under the assumption that it was because I was boiling with the lid partially on and I was getting DMS condensation on the inside of the lid and dripping back into the boil. Maybe if we cross reference our issues we can narrow it down to a few variables.

Do you boil with the lid off? I have started doing this and the issue seems better, but I have brewed pretty dark/flavorful beers lately and that could be masking it. I really think the off flavor was DMS though. I did a sensory analysis kit and the DMS added to bud light at 3x the taste threshold was pretty spot-on.

 

[doug293cz]

...

In the meantime, reduce your sparge water volume to produce a thick sparge. That way, your sparge ph won't be as high. But keep the sparge temperature high (~170F) as the whole point of the dunk sparge is to dissolve as much remaining sugar as possible.

AFTER combining the worts in the pot, then top up with more water to reach your targeted boil volume.

Bad advice! Control your sparge water's alkalinity, with acid additions if necessary, rather than reduce the volume of sparge water. Reducing the sparge water volume will reduce your mash efficiency, as will topping up with water rather than sparged wort. The more water that the grain sees, the higher your efficiency (all else being equal.)

Also, hot water is not necessary for sparging. There is no sugar to dissolve in the mash, as the sugar is created in solution. There is never any undissolved sugar present in a mash. The solubility limit of maltose in water at mash temps equates to an SG in excess of 1.300! (ref: http://chestofbooks.com/food/science/Experimental-Cookery/Solubility-Of-Maltose-In-Water-gillis.html.) You can't get the concentration of sugar in a mash high enough for sugar to precipitate out of solution. Kai Troester has compared hot water sparging and cold water sparging, and there was no difference (within experimental error.)

Brew on

 

[csdunham]

I have had this same off flavor in all my lighter beers! I do BIAB/no sparge so I don't think tannins or sparge temp are your problem. It could be a mineral addition or pH issue. I usually do 50/50 RO water and tap water with some mineral and acid additions. I use Bru'n Water for all my adjustment calculations.

I have been under the assumption that it was because I was boiling with the lid partially on and I was getting DMS condensation on the inside of the lid and dripping back into the boil. Maybe if we cross reference our issues we can narrow it down to a few variables.

Do you boil with the lid off? I have started doing this and the issue seems better, but I have brewed pretty dark/flavorful beers lately and that could be masking it. I really think the off flavor was DMS though. I did a sensory analysis kit and the DMS added to bud light at 3x the taste threshold was pretty spot-on.

I do boil with the lid off. I can't say that I know what DMS tastes like.

 

[csdunham]

If I treat all of my brew water before I divide it into the mash and sparge pots will the pH be the same during both the mash and sparge?

 

[PeteNMA]

No. There are reactions which happen during the mash which only happen once which affect the pH. When adjusting mash pH, you need to dough in, get your temp on target then leave everything for 5 minutes or so to let the pH stabilise. Then measure and adjust if necessary, either with lactic/phosphoric acid, acidulated malt or sodium bicarbonate (if used in moderation)

These reactions only happen once, so when you sparge the grain has much less influence on the pH. So you just acidify your sparge water down to about pH6.0 and let her rip.

 

[csdunham]

No. There are reactions which happen during the mash which only happen once which affect the pH. When adjusting mash pH, you need to dough in, get your temp on target then leave everything for 5 minutes or so to let the pH stabilise. Then measure and adjust if necessary, either with lactic/phosphoric acid, acidulated malt or sodium bicarbonate (if used in moderation)

These reactions only happen once, so when you sparge the grain has much less influence on the pH. So you just acidify your sparge water down to about pH6.0 and let her rip.

What happens if I sparge with distilled water?

 

[PeteNMA]

I'm stretching a little here, and a lot will depend on your system and sparging methods, but if the pH of the run-off increases too much then you start extracting tannins from the grain husks.

If you keep the pH down during sparging then you minimize/eliminate the extraction of tannins. Acidifying the sparge water also helps get your boil pH on target.

 

[TheMadKing]

I do boil with the lid off. I can't say that I know what DMS tastes like.

It tastes somewhere between bready and grainy like cooked corn or like boiling grits smells

 

[doug293cz]

What happens if I sparge with distilled water?

DI water has a pH of 7.0, but it has zero alkalinity, so it will not be able to raise the pH of your sparge significantly.

Brew on

 

[csdunham]

I'm thinking about re-brewing the exact same recipe but with my own water profile so that I can compare the two beers. I attached some screen captures of BrewersFriend water calcs. I'm starting with 3 gallons of distilled water and according to this I only need 3 grams of gypsum and calcium chloride each. Does that sound right?

 

[PeteNMA]

That sounds very reasonable to me