Monthly Archives: November 2007

Calibrating A pH Meter: Buffer Solution

Leave a reply

What is a buffer solution?

You need to calibrate your pH meter for it to work properly, but to do that, you need to immerse it in a solution of known pH. Buffer solutions are the way out of that little chicken and egg problem. These are made of precisely measured ingredients that combine to form a solution of known, and highly stable, pH. It would be pretty tough for most home winemakers to make their own buffer solution, so it’s a good thing that they’re widely available at homebrew shops.

Not all buffers are created equal

I was out of pH 4 buffer, and bought some more from a local shop. The first difference I noticed, between the new and old solutions, was the color – the new one was pink and the old one was colorless. There were two other differences, though, that were more significant. Each solution came with a temperature table that indicated the precise pH, to two decimal places, at a given temperature. The old solution listed the pH from 0C to 95C in 5 degree increments, and over that wide range the pH varied from 4.00 to 4.22. The new solution listed the pH at 20C (pH = 4.02) and 30C (pH = 4.99). The detail and temperature stability of the old solution gave me a lot of confidence. The new one is … pink.

How to shop for buffer solution

My pH meter had been pretty steady, often needing no adjustment at all between uses. When it had drifted, it was only by 0.02 or 0.03. So I was taken aback to see my pH meter read 3.74 when I first put it in the new solution. Maybe the meter drifted by that much since the last time I used it, but maybe the pH of these two “pH 4” buffers differed by 0.26. I was out of the old solution, so I couldn’t check this. The new solution is fresher, so it’s possible that the old one drifted over time, but I’ve got my doubts about the new one. Live and learn. The next time I buy buffer solution, and that’s going to be pretty soon, I’ll try to find out when it was made and how much detail is in the temperature table.

Update 5/13/2012 – Hanna buffers are my favorite

I’ve been calibrating my pH meter for five years now, and I’ve bought various brands of buffer solution. I keep going back to Hanna. I’m not a chemist, but the detailed temperature corrections and the small drift give me a sense that theirs is a cut above. They’re readily available at good prices too, so for whatever it’s worth this is what I buy.

Apple Wine Recipe

60 Replies

I got my start in winemaking by fermenting apple juice. I bought 1-gallon glass jugs, filled with juice, for less than homebrew shops were selling them empty. This got me a collection of small secondary fermenters and some nice dry white wine. I still make apple wine, almost every year, from my own apple trees and store bought juice. The apple juice will be low in acid and fermentable sugar, so I’ll have to add both. I’m using honey as my sugar source this year, but ordinary table sugar works too.

Apples on a kitchen scale reading just over 4 lb and Trader Joe's Gravenstein apple juice. The main ingredients of my apple wine.

Ingredients

4 lb 1.5 oz Liberty & Akane apples
1 Gallon Trader Joe’s Graventein Apple Juice
0.5 tsp tanninTannin is optional, but no more than 0.25 tsp/gallon
honey to SG 1.090
acid to 6-7 g/L in the finished wine
sulfite to 50 ppm (equivalent to 1 campden tablet)
1 tsp pectic enzyme
Premier Cuvee yeast from starter

Procedure

Since the Gravenstein juice is pasteurized, there’s no threat from microorganisms. So I’ll chop & juice the apples and add all the sulfite to this juice, where it’s needed most. I’ll add the pectic enzyme to the Gravenstein juice, combine them, and measure the SG, pH, & TA. I’ll raise the SG to 1.090 by adding honey.

Juice from 4 lb of apples fills a plastic measuring cup to the 4-cup line.

Here’s where the juicer that I used making my Produce Department Chablis came in handy. It made short work of the 4 lb of apples I threw at it. It does clog often, but it’s so much better than the other methods I’ve tried (sugar extraction, blender, mill & press without an actual mill or press, chop & toss in the fermenter).

Measure sugar & acid and add the honey

The apples yielded 1 quart (just under 1 liter) of juice. Adding it to the one gallon of Trader Joes juice gave me 1.25 gallons. This combined juice had an SG of 1.050, a pH of 3.52, and a TA of 5.5 g/L. Added a cup of this juice to the 2 cups of starter (Niagra juice with Premier Cuvee yeast that I used to start the Merlot and Chardonnay).

Honey, with 18% water, has an SG of 1.417. Converting my 1.25 gallons to metric measures, I have 4.7312L of 1.050 must. Adding 0.5785L honey will yield 5.31L of SG 1.090 must. I’ll round and call it 0.6L honey.

I’ll wait to add the acid

My 4.7L of juice had 5.5 g/L of titratable acidity, or about 26 grams of acid in total. Adding 0.6L of honey brought the total volume to 5.3L. A typical white wine must would have about 8 g/L, so my 5.3L ought to have about 42 grams of acid. Assuming no contribution from the honey, I would need to add about 16 grams of acid to reach my goal. I think I’ll wait for it to ferment out, take another reading and adjust the acid then. Acidity often drops during fermentation, and I’ll aim for 6-7 g/L, as tartaric, in the finished wine.

Other apple wine recipes

Growing your own apples gives you more control (you pick the varietal, decide when to harvest, and so on). Here’s an apple wine recipe using 100% home grown apples!

On the other hand, making wine from store-bought juice is quicker and easier. Much quicker and easier. So if you’re just starting out or you just want great apple wine with less work and cleanup, try my apple wine recipe from store-bought juice.

Just Do It

Leave a reply

I’ve got a freezer full of rhubarb, tomatoes, and grapes. They, and the apples in my refrigerator, are all destined to become wine. What’s the holdup? Chemicals. I need more sodium hydroxide (NaOH) to do acid titration and buffer solution to calibrate my pH meter. If I’d ordered them online, they’d have arrived by now and I’d be in business. Instead I decided I needed them fast, so I’d just pop down to the local homebrew shop and pick them up. I don’t know why I keep putting it off. Who wouldn’t jump at the chance to sit in even more traffic or squeeze into a crowded parking lot? I could order them today, of course, but then I’d have to wait for them to be delivered …

Have It Your Way

Leave a reply

One of the things I enjoy about being a wine maker is out of the box wine making. For example, most Riesling is sweet, and even “dry” Riesling often has residual sugar. It’s an acidic grape, and winemakers will tell you that they add just enough sugar to balance that acidity. The idea is to soften the acidity while leaving the wine “tasting dry.” This can improve some acidic wines, and I intend to do something like that with my cherry wine.

Could there be a Riesling that isn’t sweet? What would that be like? I boldly decided to find out. While processing the Riesling, I was determined to not cover it’s taste with a lot of sugar. I even had a tasting party when the wine was young. The idea was that my guests would sample four bottles of the Riesling with varying amount of sugar and comment on the sugar-acid balance. We had a blast and I appreciated the input but even then I went my own way.

I bottled the Riesling dry, with no residual sugar, and last weekend I put my hard work to the test. We had some friends, Ralph and Ruth, over for dinner. I served up my Sauvignon Blanc and the Riesling. I’m always interested to hear what people think of my wines but I was especially interested to hear what they thought of the Riesling. They liked it. In fact Ruth admitted she ordinarily doesn’t drink Riesling, “because I don’t like sweet wines.”

This is so common that it can be hard to find a truly dry Riesling. One nice thing about making my own wine is that I can make it just the way I like it. I made it dry and I’m glad I did.

Update 4/19/2010 – Taste blind to judge your creations objectively

The hope and excitement that go into these experiments create a lot of mental baggage, which can make it difficult to see past your own preconceptions and taste the wine objectively. But objective feedback is critical to knowing if you’re on the right track or you need to make adjustments in your wine making. Tasting blind is a great solution, and here’s a quick and easy way to do your own blind tasting at home.