Real low pH on sugar/water wash?

[Jesse]

I got my first still built, and wanted to ferment my own sacrificial run rather than buy some cheap wine or booze. Partly because I wanted to see what a sugar wash might taste and smell like, and partly because I was already heading to the grocery store, and here in OK you can't get booze at the grocery store...

Anyways, I mixed up 6 gallons of sugar and hot water until my gravity was about 1.070. Added some yeast energizer and Wyeast nutrient, along with an unspecified amount of baker's yeast I bought at the store that day too. Probably somewhere between an ounce and two ounces, if I had to guess. I pitched it straight into the fermenter once it was cooled to about 90º. I didn't go through the whole tomato paste/vitamin/nutrient thing because this was just a sacrificial run. I wasn't concerned with flavor, only that it fermented out within about two weeks. Should be easy on a straight table sugar wash, I thought. I left a few minutes later to head down to Dallas for a beer fest...

When I got back, my blowoff tube wasn't bubbling at all. I cracked the lid on the fermentation bucket to check the gravity. There was a good inch of gunk on the walls, where it looked like the yeast had gone wild. At least, that's how it looks when fermenting beer when the yeast have done their thing and fallen away. But my gravity was only down to 1.060. I let it go for another two days or so and checked again, and the gravity hadn't changed. I checked the pH, and it was at 2.5! That was far lower than I expected, and I wasn't surprised the yeast didn't like it. I added some slaked lime to get the pH up to about 4.8, and now I'm getting bubbles in the airlock every 6 seconds or so, and the gravity has been steadily dropping (1.025 now).

My question is this- do you guys typically see a pH that low in straight sugar washes? If not, any idea what could have caused the low pH? If I were to go about this again (a sacrificial cleaning run where I'm not concerned with flavor), what would you do different? I'm familiar with barley mashes for beer, but this sugar wash stuff is out of my area of expertise...

Thanks in advance!

[Kegg_jam]

Yes, pretty common for a lot of people. Depends on your water chemistry.

Get yourself some crushed oyster shells at a feed store or go to the dollar store and get a bag of sea shells. Should help with buffering the ph and avoiding a day 2 or 3 crash.

[Jesse]

Is it just a result of the CO2 causing the drop in pH? The water I used is pH of about 7.5, but without a lot of alkalinity to buffer. Even so, that seems like a huge drop just from CO2. But if that is the case, it should come back up if I degas, right? If so, the slaked lime I added will probably cause my pH to be way too high when it comes time to run it. I'll let you know how it goes...

[shadylane]

There should be a sticky about using crushed oyster shells and a yeast bomb for sugar washes.

[humbledore]

Sugar washes lead to straight low pH for me as well, I don't do them often but I always get this problem. It has nothing to do with CO2 AFAIK. They just need to be buffered from the get go. There are numerous threads on here about stuck ferments, low pH and what to use to raise pH. Sodium carbonate, sodium bicarbonate, oyster shells, egg shells, calcium carbonate, the list goes on. So I would venture that nothing is wrong with your water or process other than adding a buffer like the above. I finally got some crushed oyster shells, they do seem to be an easier solution, just dump some in from the get go.

[Jesse]

Thanks for the input guys. I realize now that pH control is necessary for a complete fermentation, not just a rapid, good-tasting one. The slaked lime I used is also known as calcium hydroxide, and is a pretty common pH adjuster, too.

I haven't been able to figure out where the extra acidity comes from though, despite a long attempt with the search feature. Can anyone explain or point me in the right direction?

In a cursory review of a yeast book I've got (Zainesheff/White), it looks like even though our summary equation for fermentation ( C6H12O6 -> 2 C2H5OH + 2CO2) only shows ethanol and CO2 being produced, there are many steps along the way which produce other acids (lots of mention of Pyruvic acid) or free protons. These are then further metabolized into the ethanol and CO2 products, but not with 100% efficiency, meaning that some are left over as acid in the wash. Can somebody who understands biochemistry better than me (which is most people) tell me if I'm on the right track here?

[shadylane]

Just a little bit of calcium hydroxide will raise the pH, sometimes too much.
A handful of crushed oyster shells will raise the pH only as much as needed. It's self adjusting.

[aladan]

There should be a sticky about using crushed oyster shells and a yeast bomb for sugar washes.

Shady, when you say crushed oyster shell where do you get them. I live near a large oyster operations and can get more than ill ever need. What is the best way to prep it and crush it? What is a good dose to say raise the PH by 1 point, say 4.0 to 5.0?

I've used calcium carbonate but find its hard to get dissolved in the wash, are oyster shells easier to dissolve?

[ranger_ric]

Go to the feed store.. They sell crushed oyster shell in 50# bags (about $9.99). It is usually near the chicken feed as it is used to supplement chickens so they have the calcium to lay eggs. I use it on ALL of my UJSSM washes. works great

[T-Pee]

Just dump a handful in the fermenter. Like shadylane said, it's self regulating and will only dissolve enough to buffer the pH to ~5.
Kinda magic shit really. I use it in all my ferments. I used to have a bad time with low pH and haven't had an issue since I started using the stuff.

tp

[moosemilk]

Jesse, you mentioned in your original post you did the sugar as a sacrificial run partly because you wanted to know how it tastes and smells, suggesting drinking it. Your sacrificial is just that, a sacrifice, you can't drink it. It has many contaminants that the steam and vinegar run don't pick up. Some members didn't believe so, and found out the hard way after violently relieving themselves from both ends for several hours, plus a headache from hell and more. Use it to start your bbq

[Jesse]

Thanks for the info guys. Don't worry moose, I was talking about tasting the wash, not the distillate

I let it ferment out to about 1.005 and then ran it. I'd have fermented further, but noticed my fermentation bucket was leaking from the spigot, and had to do an emergency transfer. I put it into the boiler, but it wasn't sanitized, so I wanted to run it before any bugs/infections took over. Worked just fine! On to some rum and whiskey!