Baking Soda in Mash Cap?

[DPlan00]

I am brewing a 12 gallon batch of robust porter using 1 1/2# Chocolate malt and 12 oz. of Black malt. I have brewed this batch before, in September, and failed to take detailed notes. I added about 8g of baking soda to the grist before doughing in in order to raise mash ph, but how I did it eludes me.

This is because I held the black malt back until the vorlauf right before mash out when I capped the mash with it. I can't remember if the 8g of baking soda was in the main mash, or if I split some between the main mash and the cap.

The beer that resulted the first time was my highest scoring beer in a comp, 43.5 points. This is why detailed notes are important. Also, the last time I brewed this, I took no ph readings, so I can't tell you where it was at. What resulted in flavor was a very smooth, not acidic, chocolatey porter. If anything, it could've used a touch of roast, I am adding a couple ounces more of black malt this time around.

Any advice would be appreciated, as I am brewing this again this coming Wednesday. Would you:
1) add all baking soda to main mash? or...
2) split baking soda addition (4g main mash and 4g with the cap)? or...
3) throw all dark malt and all baking soda into the main mash?

Thanks in advance!

 

[Nateo]

Are you sure you need excess alkalinity? I brew dark beers with fairly soft water and I need to raise the mash pH maybe 1 time out of 20. Adding alkalinity without measuring pH is not a great idea.

Baking soda = sodium bicarbonate. I don't care for salty beer. It's not ideal to raise pH. Pickling lime would be better. It's much stronger so you don't need to add as much.

 

[mabrungard]

I do like sodium notes (that means a little bit) in my darker beers, but be careful on overdosing with sodium. It gets harsh tasting quickly. If both sodium and the alkalinity were needed, then the baking soda is a logical choice.

If all the roast malts were held back, there may not have been a need for the alkalinity in the first place. I assume that the brewing water has really low alkalinity and there is some need for alkalinity in that brew.

If the mash pH was just a little high, I find that that helps smooth the flavors. That slightly elevated mash pH also helps extract the flavor and color from the roasted malts. That's the good part. If you go overboard on the mash pH, then the potential for tannin extraction goes up.

I don't know how this brew stacks up with its alkalinity and grist acidity, so any of those 3 scenarios might be OK. Off hand, I'd say that the mash didn't need the baking soda if the roasted malts are reserved. Some brewers like the flavor difference that is created when they brew with low alkalinity water and reserve the roast malts to the end of the mash. If all the roast is added with the main mash, then some baking soda might be beneficial if the starting water has low alkalinity.

 

[DPlan00]

Thanks for the replies. The water has an alkalinity of 97. Is that considered low? I found that the first time I brewed the beer that the flavors from the darker grains were just right, I just wish I could remember how much I added/when.

According the the EZ Water Caluculator, my mash pH would be 5.60 with the grain bill I am using. This is on the high end already, isn't it?

 

[mabrungard]

5.6 is just slightly high. That suggests that less baking soda is needed. 97 ppm alkalinity is not low. The alkalinity might be high enough to avoid the need for baking soda in the first place.