Oyster shells as a pH buffer?

[masonsjax]

I noticed that the distilling forums are loaded with folks that advocate fermenting a wash with a bunch of oyster shells thrown in to buffer the fermentation pH. They claim that if the pH is low, the shells will dissolve, thus raising the pH and that they will stop dissolving when an appropriate pH is reached. There is no measuring or calculation involved, just throw a bunch in and call it a day.

Having read a lot of the info about the ineffectiveness of products like 5.2, I doubt it's as simple as these guys think, but I haven't been able to find a shred of info about the oyster shell method here on HBT. So, what's the deal?

 

[theheroguy]

I noticed that the distilling forums are loaded with folks that advocate fermenting a wash with a bunch of oyster shells thrown in to buffer the fermentation pH. They claim that if the pH is low, the shells will dissolve, thus raising the pH and that they will stop dissolving when an appropriate pH is reached. There is no measuring or calculation involved, just throw a bunch in and call it a day.

Having read a lot of the info about the ineffectiveness of products like 5.2, I doubt it's as simple as these guys think, but I haven't been able to find a shred of info about the oyster shell method here on HBT. So, what's the deal?

Assuming this true it might be problematic for

1: The ideal distilling mash ph may differ from that of beer

2: Distillation may remove flavors from oyster shells.

 

[Qhrumphf]

Assuming this true it might be problematic for

1: The ideal distilling mash ph may differ from that of beer

2: Distillation may remove flavors from oyster shells.

I'd say trying it with a stout is probably the safest bet, since oyster stout is a known working combo. Can't say the same for other styles.

 

[trentm]

Oyster shells are largely calcium carbonate (chalk) and may react similar in mash. So it's likely that they would not dissolve in time to do anything in the mash and may, like chalk, later raise the pH of the finished beer to its detriment. In The Gambia, where the Gambia river enters the ocean on the West Coast of Africa, the banks are composed of solid walls oysters shells that have built up over time. Local people harvest the shells, crush, and burn them. As soon as they are cool they are mixed with water. This process creates slaked lime. Then the slaked lime is used to make mortar to lay concrete blocks, or add crushed shells for aggregate to make concrete. We know that slaked lime has a near instant effect of raising mash pH. So if you are so inclined to crush and burn the shells you can certainly raise the mash pH.

I believe the use of oyster shells (whole or crushed) to adjust mash pH is probably derived from the old idea of using chalk to adjust the mash. It makes sense but probably doesn't work.

 

[MrFancyPlants]

I've thought of using eggshells in a similar manner, but as an adjunct in cider to decrease the final acidity.

 

[masonsjax]

These guys are putting them in during fermentation, not in a mash. I think they're talking about sugar wash mostly where pH may be too low for yeast to get going ?? For us, I guess it's irrelevant because if we get a good mash pH, the kettle pH should be in line, and yeast will fine tune from there. I just wrinkled my nose at the idea of throwing shells in your fermentation without any further thought.