Cause of astringency?

[briggssteel]

Most of my beers lately have had astringency. Not over the top, but it's there. I think I may have found the culprit. When I recirculate/sparge I always end up with grain particles coming through. I took a preboil sample and there was about a couple inches of grain particles that settled in the hydrometer tube. Then of course I take this to the boil and I'm wondering if that's that's where my astringency is coming from. I'll recirculate 4 or 5 times and it'll run clear but then grain particles will start coming out anyways.

Some extra info, I'm batch sparging in a 10 gallon igloo cooler. I'm using a false bottom but it doesn't cover the whole bottom. I got it pre made at Midwest supplies. I'm wondering how I can filter the grain particles out a little better. Thanks!

 

[passedpawn]

Don't batch sparge more than twice. Once for low OG beers.

Each time you sparge, the pH of the mash increases. If it gets too high, the tannins are leeched from the barley husks. This is the science as I learned it.

 

[LLBeanJ]

You can line your cooler with a bag, a la BIAB, which would give you an added filter. Or you could add a filter or manifold to your outlet to work in tandem with the false bottom. I've heard that those stainless steel scrubbing pads work well as a filter.

Just out of curiosity, do you monitor your mash pH? Having grain in the boil is not great, but I'm not sure it would cause the issue you're describing, whereas a high mash pH definitely would.

 

[Yooper]

It does sound like a pH issue- either a too-high mash pH or during the sparge.

Do you know your water chemistry? Is this in all beers, or only certain ones like lighter colored beers?

 

[henchman24]

What is your water chemistry and what are you adding to it?

Don't batch sparge more than twice. Once for low OG beers.

This and/or acidify your sparge water a bit.

For the grain, how much care are you taking to not disturb the grain bed when you are recirculating? Bags can help, but if you are disturbing the grain bed too much, they won't help.

 

[briggssteel]

Thanks for the responses. I only batch sparge once. What I meant was that I'll collect a quart or two dump it back in the top 4 or 5 times until it's no longer cloudy for first runnings and sparge. Also I only brew with RO water and typically add calcium chloride or gypsum to get the calcium at adequate amounts. I've heard sparge PH isn't an issue with RO but I could be wrong. My last batch was a Kolsch that did ok in competition with a 27.5, but astringency was the biggest detractor for the judges. I didn't do anything to lower that mash PH nor did I take a reading. I just added a teaspoon of calcium chloride. I think I calculated it coming in at 5.6-5.7 with Bru n water. I probably should have added some lactic acid.

I like the idea of adding a bag as an extra filter. I bet cleanup would be a lot easier as well.

 

[briggssteel]

What is your water chemistry and what are you adding to it?



This and/or acidify your sparge water a bit.

For the grain, how much care are you taking to not disturb the grain bed when you are recirculating? Bags can help, but if you are disturbing the grain bed too much, they won't help.

I typically just pour it back in and try not to get too crazy and pour somewhat slowly. This last batch I put a piece of foil at the top so it would take most of the force of the pour. I still has a good amount of grain coming out but the batch was sort of atypical because I used a can of pumpkin and quite a bit of rice hulls. I kept getting a stuck sparge and had to mix it back up more than once.

 

[Yooper]

With RO water, you don't have to acidify your sparge water as long as you are sure it's actually good quality RO water.

For the mash pH, 5.7 is acceptable, but it's on the high side. I'd suggest trying to mash at 5.4 or thereabouts, and generally with light grainbills you may need some phosphoric or lactic acid, even with RO water.

What is your RO source? It sounds like it may not be pure RO water, and have a too-high alkalinity if you're getting tannins.

 

[helibrewer]

For lighter beers, I replace 3-4oz of the base malt with acidulated malt, I also use treated RO water. Keep Ca above 80ppm, add a little acid malt and you should easily be 5.3-5.4 on the pH.

 

[RichBenn]

Although high ph at the end of sparging can be a cause of astringency, I certainly have introduced astringency by getting grain particles in the boil, and that was with a bazooka style screen even. With some false bottoms, and the fine grind one uses to help efficiency in batch sparging, the problem can be worse.

A couple of husks in the boil will probably never show up in the final product. When I got astringency in the final product on a batch sparge, I had disturbed the grain bed and did not further filter the wort before boiling, so I imagine there was a bit in there.

Here is what I do to help eliminate the problem(assuming batch sparging):

1. Use a double mesh stainless strainer when collecting wort. I'm usually batch sparging to speed things up, so a little secondary catcher does catch most particles that fall through the filter bed. Good insurance. An earlier comment about using a BIAB bag inside the mash tun is another great way.
2. Recirculate carefully. Make certain you have a column of liquid above the grain bed when recirculating, otherwise you risk disturbing the filter bed. If you disturb the filter, you will get particles through. You don't even need to recirculate much more than a quart typically; it doesn't have to be crystal clear.
3. Grind your own grain. I recently got a false bottom for fly sparging and HERMS; holes are way bigger than my mesh bazooka tube. I'll grind finer on the mesh tube or BIAB than the false bottom.
4. Balance your water and check your final runoff pH. Ok, a big nod to the other astringency possibility mentioned here. There is a great spreadsheet in the brew science forum that you can use to adjust for different styles to keep your brewing pH fine. But checking your pH during mashing and the last draining will tell you if you have any problems. High efficiency AND lack of astringency is possible.

Edit - Oh, and I don't think anyone mentioned sparge temp as another possible cause, although most don't get batch sparges above 168.

 

[briggssteel]

With RO water, you don't have to acidify your sparge water as long as you are sure it's actually good quality RO water.

For the mash pH, 5.7 is acceptable, but it's on the high side. I'd suggest trying to mash at 5.4 or thereabouts, and generally with light grainbills you may need some phosphoric or lactic acid, even with RO water.

What is your RO source? It sounds like it may not be pure RO water, and have a too-high alkalinity if you're getting tannins.

It was "drinking water" from Walmart or target I believe. The kind that comes in gallon jugs. I'm pretty sure that water is run through an RO filter it says.

 

[Yooper]

It was "drinking water" from Walmart or target I believe. The kind that comes in gallon jugs. I'm pretty sure that water is run through an RO filter it says.

I would definitely check that- maybe a cheap TDS (total dissolved solids) meter, or even an aquarium testing kit for hardness could tell you right away if the water has too much bicarbonate in it. It does sound like the mash and/or sparge pH is too high, from the description of the problem (astringency).

 

[Yooper]

Although low ph at the end of sparging can be a cause of astringency, ................

I know you meant high pH, but for clarification for others I wanted to make sure that others knew that it's a too-high pH that we're talking about it, and not low pH, as a too-low pH at the end of sparging would be impossible to get without adding acid to the water and even then it would be tough to get !

 

[RichBenn]

I know you meant high pH, but for clarification for others I wanted to make sure that others knew that it's a too-high pH that we're talking about it, and not low pH, as a too-low pH at the end of sparging would be impossible to get without adding acid to the water and even then it would be tough to get !

Oops! Thanks for the fix! I'll edit above so it's less likely someone will get screwed up.

 

[RichBenn]

It was "drinking water" from Walmart or target I believe. The kind that comes in gallon jugs. I'm pretty sure that water is run through an RO filter it says.

Drinking water and RO are different. You want minerals in drinking water for taste, so you'd have to know what they did with it to balance it. Almost made that mistake once, at Walmart with their machines. But I'm a label reader, and reading carefully, they didn't say, nor did anyone know.

Drinking water would typically be in the 200 + PPM range, AFAIK. Could be RO filtered then minerals added, or just lightly filtered with a carbon filter for taste. You may be better off with drinking water just using as-is than adding something to water that already has minerals in it for taste.

Pure RO is not sold in gallon jugs in department stores(again, AFAIK). Although not quite distilled water, RO typically will have such low TDS (20's PPM), you can effectively assume it has nothing in it and balance like it was distilled. I used distilled water in the gallon jugs when I was on hard city water, as the city blended from different sources of water so you couldn't predict anything, and I didn't have an RO filter, nor could I find anything else but drinking water close by. The best, IMHO, is to get your water tested or use the test data from your region's water company and balance from there. (Removing chlorine, of course)