Astringency concerns with sparging 10 gallon batch of low gravity ale

[rwing7486]

Hey Everyone,

I am looking to brew a 10.50 gallon batch of a low gravity cream ale where my plan is to to split the wort into two fermenters to do a side by side comparisson of fermenting with two different yeast - WY1056 (American Ale) and WY2112 (California Lager). Below you will find my recipe for reference.

My concern is with my grain bill being so small for a 10.5 gallon batch (15.5 gallons) is even if i use a mash thickness of 1.75 my sparge volume is still at 8.75 gallons. I feel if i sparge with this large of volume I risk extracting tannins. Should i be concerned?

Recipe Specifications
--------------------------
Boil Size: 13.44 gal
Post Boil Volume: 11.72 gal
Batch Size (fermenter): 10.50 gal
Bottling Volume: 10.10 gal
Estimated OG: 1.046 SG
Estimated Color: 2.9 SRM
Estimated IBU: 17.7 IBUs
Brewhouse Efficiency: 78.00 %
Est Mash Efficiency: 83.6 %
Boil Time: 90 Minutes

Ingredients:
------------
Amt Name Type # %/IBU
6 lbs 8.0 oz Brewers Malt (2 Row) US (2.0 SRM) Grain 1 40.0 %
6 lbs 8.0 oz Pilsner (2 Row) Ger (2.0 SRM) Grain 2 40.0 %
2 lbs Corn, Flaked (1.3 SRM) Grain 3 12.3 %
8.0 oz Cara-Pils/Dextrine (2.0 SRM) Grain 4 3.1 %
12.0 oz Corn Sugar (Dextrose) (0.0 SRM) Sugar 5 4.6 %
1.50 oz Cascade [6.30 %] - Boil 60.0 min Hop 6 17.7 IBUs
2.10 Items Whirlfloc Tablet (Boil 15.0 mins) Fining 7 -
1.00 oz Liberty [4.30 %] - Boil 0.0 min Hop 8 0.0 IBUs
1.0 pkg American Ale (Wyeast Labs #1056) [124.21 Yeast 9 -


Mash Schedule: Single Infusion, Light Body, Batch Sparge
Total Grain Weight: 16 lbs 4.0 oz
----------------------------
Name Description Step Temperat Step Time
Mash In Add 27.13 qt of water at 159.2 F 151.0 F 75 min

 

[Smellyglove]

"Probably" if you don't adjust your water. I'd rather do that small grist the no-sparge way. Lower efficiency meaning you need to use more malt, and you will not extract more of the malt than what's in your MT.

 

[rwing7486]

I do plan to adjust my water. I am using 100% RO water and using Bru' n water to adjust my water. I will be adding 3.6g Gypsum and 3.1g CaCl, and 1.9ml of lactic acid to 6.9gallons of strike water to get my mash pH where i want it. For my sparge water I will be adding 4.6g gypsum and 3.9g CaCl. I think the smart thing to do is to measure the pH of my sparge water and see if I have to add any lactic acid to keep it under 6.0. I guess my bigger concern is over sparging to reach my target pre boil volume. If my sparge runnings drop to 1.008 i risk extracting tannins. So if i meaure my runnings while sparging and i reach 1.008 before i get to my pre boil volume i will be stuck between a rock and a hard place.

 

[Yooper]

Yes. With a lower grainbill, you do risk oversparging. Just don’t sparge below 1.008, and you’ll be ok. If you’re not yet at your preboil volume, you can top up with RO water if you want to reach that volume.

 

[Smellyglove]

Yes. With a lower grainbill, you do risk oversparging. Just don’t sparge below 1.008, and you’ll be ok. If you’re not yet at your preboil volume, you can top up with RO water if you want to reach that volume.

Extraction of tannins is also cause of pH. 1.008 is btw pretty low. Even though tannin extraction is "less" with correct pH, I wouldn't go that far. But, it all depends..

For what it's worth. A few years ago, without using acid, if found out that at least at 70/30 sparge/mash water the tannin extraction was severe. Didn't go under about 1015 for last runnings. Soft water light beers.

 

[chickypad]

Like Yooper said just top off with water if needed, or batch sparge this one.

 

[rwing7486]

Thanks Everyone, I will probably stop sparging at 1.010 to be safe and then top off like you said

 

[homebrewer_99]

Thanks Everyone, I will probably stop sparging at 1.010 to be safe and then top off like you said

I usually stop at 10 myself. Just remember to adjust the gravity reading for temperature.

 

[rwing7486]

I usually stop at 10 myself. Just remember to adjust the gravity reading for temperature.

Ya that shouldnt be an issue as I have a refractometer as the small sample size will cool quickly

 

[homebrewer_99]

Ya that shouldnt be an issue as I have a refractometer as the small sample size will cool quickly

That's when I use mine too.

 

[mabrungard]

In my experience, pH or temperature aren't really what drive tannin extraction. It is the final runoff gravity that drives it.

I had used that 2 Brix cutoff rule for years and it worked reasonably well when I was getting poorly milled grain from my homebrew shop. But when I bought a good mill and conditioned my malt, my efficiency went way up and the tannin problem started rearing its head. I finally solved it by reducing the amount of sparging water added to the tun, stopping runoff at 4 to 5 Brix, and adding the extra sparging water, as needed to top up the kettle volume.

 

[rwing7486]

In my experience, pH or temperature aren't really what drive tannin extraction. It is the final runoff gravity that drives it.

I had used that 2 Brix cutoff rule for years and it worked reasonably well when I was getting poorly milled grain from my homebrew shop. But when I bought a good mill and conditioned my malt, my efficiency went way up and the tannin problem started rearing its head. I finally solved it by reducing the amount of sparging water added to the tun, stopping runoff at 4 to 5 Brix, and adding the extra sparging water, as needed to top up the kettle volume.

Martin when you reduced your sparge volume did you thin out your mash thickness? If so what did you use? currently I have a mash thickness of 1.50 planned which equates to 5.25 gallons strike water and 7 gallons sparge. With this low of gravity do i thin the mash by bumping it up to 1.75 or even 2? Right now my initial thinking is leave at 1.50 and sparge with using 5 of the 7 gallons and monitor the gravity of the run off. If it dips low then stop the run and top off the kettle with the remaining 2 gallons I have.


Im finally getting around to brewing this beer this weekend to be ready for 4th of July.

 

[mabrungard]

The sparging volume was reduced only with respect to the amount actually placed in the mash tun. I reserve about a gallon of water (out of about 5) that is NOT added to the tun. That reserved volume is added, as necessary, to achieve my desired start of boil volume in the kettle.

 

[couchsending]

Just set your efficiency lower, make less volume of a higher OG wort, and top up with water.. the few extra bucks in base malt is well worth a smoother more enjoyable beer. The higher the gravity of the last runnings the better.

 

[rwing7486]

Everything went smoothley yesterday. Hit all my numbers and didnt over sparge. I sparged with 6.5 gallons out of my total 9.75 gallons where my last runnings were coming out of the tun at 1.016. I topped off with the remaining sparge water until i was at my desired pre boil volume (~3 gallons needed). Hit my predicted pre boil gravity of 1.036 based on 80% efficiency. Thanks you everyone for your input and suggestions.