Test Mash Question - First Time Test Mash & New pH Meter

[Jiffster]

I have my new Hach Pocket Pro+ meter and supplies and I am preparing for my next brew.

I have never used the meter before and I have never created a test mash before to determine mash pH and adjust accordingly.

I am going to be brewing Biermuncher's Black Pearl Porter from this thread:

https://www.homebrewtalk.com/showthread.php?t=24243

Based on this recipe (also shown below) would I just add 10% to the grain bill when picking up my grains so I can then take 10% of the grains and prepare a test mash?

When I prepare the test mash, what water/grain ratio would I use?

If anyone could provide the critical information on how to do this, I would appreciate it. (or even detailed if you are so inclined).

Thank you.

ALL GRAIN - 5 Gallons
8.00 lb Pale Malt (2 Row) US (2.0 SRM)
2.00 lb Munich Malt - 10L (10.0 SRM)
1.00 lb Caramel/Crystal Malt - 30L (30.0 SRM)
1.00 lb Chocolate Malt (350.0 SRM)
1.00 lb Oats, Flaked (1.0 SRM)

0.50 oz Fuggles [4.52%] (60 min)
0.50 oz Fuggles [4.20%] (2 min)

0.25 tsp Irish Moss (Boil 10.0 min)

1.00 cup Malto-Dextrine (Boil 20.0 min)
4.00 oz Lactose (Boil 15.0 min)

1 Pkgs London Ale (Wyeast Labs #1028)


Mash Schedule: Single Infusion, Full Body, Batch Sparge
Total Grain Weight: 13.00 lb
Mash In Add 4.06 gal of water at 170.5 F 158.0 F 45 min
Mash Out Add 2.50 gal of water at 206.7 F 175.0 F 15 min

 

[SpeedYellow]

When I prepare the test mash, what water/grain ratio would I use?

If you're using 10% of your grains for the test mash, then use 10% of your strike water too. In other words, keep the same water-to-grain ratio in your test mash.

P.s. of course, estimate the amount of lactic/phosphoric acid (or acid malt) needed and add that to your test batch too (once again, 10% of the total needed for the batch). Then adjust accordingly for your main mash.

 

[Jiffster]

I thought the test mash should be w/o additions so you can determine what the base line pH is in order to determine what acids to add to achieve desired pH?

 

[oujens]

I believe the idea is to do as if you were mashing your full batch. That way you can determine if you need to adjust your additions to reach your target pH. If you don't add anything to the mash you will not know how the mash will react once the additions are made.

 

[SpeedYellow]

If there's a target pH you want to hit, you'll obviously do a far better job hitting it if you add acid to the test mash then tweak the amount needed for the full mash.