My New Toy: Refractometer (and bonus Christmas Cider recipe)

A couple of weeks ago, I was looking through Google Plus communities and I came across a post on using a refractometer for measuring sugar concentration (i.e. Brix). For me, this was a lightning bolt. I didn't need to read anything beyond the title of the post to know exactly why I wanted my own refractometer and why. I immediately started looking online, and found out that Lee Valley Tools in Edmonton had one in stock, advertised as a "Sugar Tester", priced at $76.50. I acquired one the next day.

Portable Refractometer. The item came with a case, an eyedropper, a small

screwdriver (for the calibration screw), instructions, and a cleaning cloth.

A refractometer measures the index of refraction of a medium. The index of refraction, n, is the ratio of the speed of light in a vacuum compared to the speed of light in the medium of interest. For example, n for water is 1.333, which means that light travels 1.333 times slower in water than in a vacuum. Refraction is when light "bends" on entering a medium with a different n. When I described this to my daughter, she immediately gave the example of looking at a plastic straw in a glass of water - it looks like it's bent.

The key thing to know is that sugar solutions have a larger n than water. And, if you increase the sugar concentration, n increases. This can be calibrated and you can use a relatively simple optical measurement to determine sugar concentration, as opposed to measuring specific gravity with a hydrometer.

Personally, I find the measurement of specific gravity with a hydrometer to be a chore. For one, you need to sanitize the hydrometer and the cylinder or wine thief used to hold the liquid during the measurement. So, every time you want to measure s.g., you need to sanitize stuff. Second, hydrometers are made of glass, so they are fragile and it's no fun if you break one by accident. Third,  s.g. measurements are a bit imprecise due to the size of the meniscus relative to the calibration marks on the hydrometer. And, if there are bubbles stuck to the hydrometer, the s.g. reading will be higher than it should. You need to measure s.g. two or three times to make sure the reading is consistent.

Measuring Brix with a refractometer is just simple. All you do is place a few drops (yes, DROPS) of liquid on the prism, close the "daylight plate", and look through the eyepiece for the reading. In this particular refractometer, the dual scale is given in Brix and "Approximate % of Alcohol". The images below show what you see in the eyepiece.

Refractometer Brix scale with water on the prism.

(Photo obtained by placing the eyepiece up to the camera on a MS Surface tablet)

Refractometer Brix scale with freshly pressed apple juice (for cider, of course!)

My first use of the refractometer was in preparing a batch of cider. I decided to use the same 'recipe' as a batch from last year, which I'm going to name "Christmas Cider" (see recipe at the end of this post). That batch of cider was delicious and I wanted to reproduce it. The refractometer comes in handy because I diluted the apple juice by a factor of two with water, and then adjusted (increased) the sugar content in order to get enough alcohol. By having a quick & easy way to measure Brix with a refractometer, this sugar adjustment was painless compared to repeatedly measuring s.g. with a hydrometer. The readings were precise in the sense that they did not fluctuate during the reading (unlike a bobbing hydrometer!) or between readings of the same sample.

The one big limitation of measuring the index of refraction is that it's only really useful for measuring sugar content before fermentation starts. When fermentation starts, the sugar concentration decreases, and alcohol increases. Alcohol, just like sugar, increases the index of refraction. That means that the n measurement is no longer proportional to sugar concentration. Rather, n is affected by sugar and alcohol concentrations. Apparently there are online calculators that allow you to calculate sugar and alcohol concentrations from a mid-fermentation refractometer reading, so long as you know the starting Brix. This sounds fine in theory, but I have a bias against "black box" calculations like that. Even though it's a chore, you are probably going to get a more reliable measure of fermentation progress from a direct measurement of s.g. with a hydrometer. Give me the choice, and I would rather have a direct measurement than a value from a black box. That being said, it would be interesting to compare s.g. measurements with corrected refractometer readings using an online calculators.

From a quick survey of YouTube videos on refractometers, it seems that a number of home brewers like to use refractometers when they are making up their wort, and then they use hydrometers once fermentation is under way. This makes a lot of sense.


Christmas Cider

1.5 gallons freshly pressed apple juice
1/2 tsp peptic enzyme
2 tsp yeast energizer
3 crushed Campden tablets
1.5 gallons water
approx. 3 cups granulated sugar
1 packet of champagne yeast (Lalvin EC-1118)
1 tsp. nutmeg
5 cinnamon sticks
3/4 cup dextrose (priming sugar)

Instructions*:
Add peptic enzyme, yeast energizer, and Campden tablets to the apple juice and let it sit in the closed primary fermentation bucket for 24 hours. Then, add water and stir thoroughly. Add sugar in 1 cup increments, stirring thoroughly after each addition, and measure Brix with a refractometer until Brix = 9. (If measuring s.g. with a hydrometer, aim for s.g. = 1.035 - 1.040.) Sprinkle yeast on surface of the juice and close the lid loosely on the primary (you can also use a primary with airlock). When the foam collapses, siphon the cider into a sanitized 3 gallon carboy for secondary fermentation. At this point, add the nutmeg and cinnamon sticks. Seal the carboy with an airlock. When fermentation is complete, siphon the cider into bucket and mix in the dextrose (1/4 cup per gallon of cider). Bottle in beer bottles and seal with bottle caps.

*Note: This is a customized version of the apple cider recipe in the Winemaker's Recipe Handbook, known as the purple booklet

Apple Cider 2016

The last time I made cider (see post here), I was failed by EZ Cap bottles, which just didn't hold any pressure. This resulted in a batch of still cider. Still cider is fine, but I aspire to make carbonated, homemade cider. One of the reasons I wanted to make homemade beer was to get beer to carbonate in the bottles, using standard bottle caps. That worked out just fine (see Festa Brew "Continental Pilsner). So, it was time to revisit cider-making, and attempt natural carbonation in the bottles.

Tanya and I picked the apples off of our tree, and made the fatal decision that there were enough apples that we could simply cut them up by hand before pressing. That was crazy - the manual labour to cut up all of our apples up into eights (or smaller) was just too much. Next time, I'm going to obtain a fruit crusher like last time.

The pressing however, went fairly well, and we obtained approximately 4 gallons of apple juice. The specific gravity of the apple juice was 1.034, which was almost identical to juice from the last time we pressed apples. To this, I added 4 crushed Campden tablets, 2 tap. yeast energizer, and 1 tsp. of peptic enzyme. After 24 hours, I added a packet of Lalvin EC1118 yeast, by sprinkling it on the surface. Fermentation was well underway a day later.

Primary fermentation proceeded quickly. Four days after adding the yeast, the foam on the surface had collapsed and it was time to transfer to a carboy. The volume (4 gallons) created an opportunity for two separate batches. I siphoned the bulk of the cider to a 3 gallon carbon and placed an airlock on it. This batch is meant to be regular cider.

Spiced Cider

The remainder (which amounted to a little over 1/2 gallon) went into a 1 gallon jug which I topped up with distilled water to which I had added 1 cup of sugar. This was done to get the alcohol level up to where it should be. If I did not add any more sugar, this would have been a 1:2 dilution, and the cider would be very weak). I also added 1/4 tap of nutmeg and two cinnamon sticks for flavour. I sealed the jug with an airlock.

Regular cider (left), and spiced cider (right). Fine solids are settling out.

After four days in the carboy, fermentation of the regular cider was virtually complete, and the bulk of the fine solids had settled. It was time to add priming sugar and bottle! So, I siphoned the cider to a large pail, added 3/4 cup of dextrose, stirred thoroughly, and bottled it just like you would beer. The yield was 4 x 1 L bottles, and 22 x 330 mL beer bottles.

I bottled the spiced cider one day later, adding 1/4 cup of dextrose to the (approx.) 1 gallon of spiced cider. Yield was 10 x 355 mL bottles.

A taste test of the spiced cider revealed a beverage that tasted like Christmas. The nutmeg and cinnamon paired well with the apple and the little bit of sweetness from the priming sugar. It remains to be seen how the spices affect the taste when the cider is carbonated and dry. I can't wait!

According to the purple "Winemaker's Recipe Handbook", you should age the cider for three months!!! This seems like a long time. I might get impatient and open a bottle in a month or so, just to see how it's coming along.

The Limitations of EZ Cap Bottles

For about two weeks now, my cider has been sitting in those cool looking EZ Cap bottles.  Two days after bottling the first batch, I noticed tiny bubbles rising to the top, inside the bottles.  I thought this was a good sign, as it meant that the secondary fermentation was working, and the cider should be nice and carbonated when it was all over.  The problem is that the bubbles have not stopped.  That can only mean one thing:  the EZ Cap bottles leak.

Bubbles can only form if there is somewhere for the gas to go.  If the bottle is under sufficient pressure, the CO₂ stays dissolved in the liquid, and there are no bubbles.  However, as soon as the pressure drops, CO₂ becomes gas, and bubbles become visible.  This is exactly like opening a pop bottle.  When you unscrew the lid, the pressure inside the bottle drops, and CO₂ is released.

In exactly half of my 1 litre EZ Cap bottles, tiny bubbles are still forming in the cider.  Last night, I decided to open one of the leaky bottles and test it.  When I popped open the lid, there actually was an audible pop as if the bottle was under a small amount of pressure.  When I poured a glass, however, the cider was clearly not carbonated.  (So, I added some club soda and proceeded to enjoy!)

I really like EZ Cap bottles.  They look nice and they are easy to use.  I think they are perfect if your goal is to make still cider (i.e. non carbonated).  But if you want carbonated cider, you will need to use beer bottles and bottle caps, or maybe a plastic pop bottle with a tightly screwed lid.  Now, my experience might not be a total failure.  I still have hope for the other bottles of cider that don't have bubbles, because that suggests they are under pressure.  But here's the thing - a 50% success rate of getting a strong seal just isn't good enough for this purpose.

Here's my question:  Is there a trick to getting a good seal on EZ Cap bottles?

Bottling Cider

Yesterday, once I concluded that the fermentation was complete, I racked apple cider v.1 into a clean 1 gallon jug.  A secondary fermentation is required to carbonate the cider, so I stirred in some extra sugar - recipes often call for 1/4 cup of sugar per gallon.  I added a little less than this and stirred it until it was dissolved.  Then, I siphoned the cider into three 1 Litre EZ-Cap bottles.  The plan is to wait 2-3 months before I crack open a bottle.  This should be plenty of time for the secondary fermentation to be complete, and the lees to mostly settle out.

EZ-Cap Bottles.  Don't they look good?

Apple Cider, Apple Wine

As I write this, the room is nice and aromatic, full of the smell of apple.  It seems to me that fermentation enhances the richness of fruit aromas.  It's fantastic.

Here's what I did with all that pressed apple juice.

Apple Cider v.1

This cider is made from the apples from our own small apple tree in the back yard.  It is a Norkent variety that is hardy in our northerly climate.  The yield of apples was modest, and we only obtained about 1 gallon of juice.  I added one crushed Campden tablet to the juice.  Specific gravity of the juice was 1.035, so I added 1.5 cups of sugar, bringing s.g. to 1.050.

Once transferred to a 1 gallon jug, I added 1/4 tsp. of peptic enzyme and 1/4 tsp. of yeast nutrient, stirred.  I was perhaps a little bit too eager and went ahead and sprinkled about 1/3 of a packet of sparkling wine yeast on the surface.  From various recipes and instructions, it seems that peptic enzyme may work better prior to adding yeast and starting fermentation, but I don't see any scientific reason for why that would be the case.  Anyway, I went ahead and added the yeast and placed an airlock on the jug and waited for the magic to happen.

Cider fermentation

Apple Cider v.2

All the other apples that we obtained from generous friends produced in total about 4.5 gallons of juice.  This time, I more or less followed the instructions in the Winemaker's Recipe Handbook (the "purple book").

I added 4 Campden tablets, 1 tsp. of peptic enzyme, and 2 tsp. of yeast nutrient.  The specific gravity for this apple juice was the same as the first batch (1.035).  I added enough sugar to bring the density to 1.055.  I let the juice sit for 24 hours before transferring 3 gallons to a carboy and adding the yeast.


Apple Wine

There was a lot of leftover apple juice from the above cider batch, so I improvised a batch of apple wine.  I diluted the juice to just over 3 gallons, added sugar until the specific gravity was 1.090, and then added a packet of sparkling wine yeast.  That's all.  This batch is currently fermenting away in a plastic bucket with a loose fitting lid.

My plan is to add some spices to the wine when I transfer it to the secondary.  (Does anyone have suggestions on what to add?)

How do you like them apples?

Today, the aromas in my home office/fermentation room are lovely.  There are three separate fermenters in action: two with apple cider and one with an apple wine.  The air is filled with methyl butanoate (the main ester compound that contributes to the smell of apples) and a number of other minor compounds that contribute to the fruity atmosphere.  If I keep the door closed, the aromas build up and become a bit of a distraction.

A couple of days ago, I decided to go ahead and try making apple cider and maybe also apple wine if I had enough apples.  Our own apple tree is still small, and our harvest consisted of a single cardboard box full of apples.  My wife sent out an A.P.B. to her friends to see if anyone had apples they wanted to dispose of, and we quickly obtained an additional 4 cardboard boxes full of apples.

I rented a fruit crusher and press from my favourite store, Wine Kitz - St. Albert, and got to work producing fresh apple juice on our patio.  This was by far the most fun I have had in making fermented beverages. 

The fruit crusher (see picture) consists of a rotating shaft with sharp blades that chop up the fruit into smaller pieces.  Chunks of fruit are drawn into the space between two rotating metal rollers that crush the fruit.  The crushed fruit and juices can be collected in a bucket placed below the device.  Initially, we used a plastic pail to collect the mashed apples, but then switched to a large blue recycling box lined with a garbage bag.

The Crusher: put apples in the hopper and turn the wheel

We dumped the crushed apples into the wine press.  The wine press was fun to use.  Two thick semicircular wooden discs go on top of the fruit, and then you put enough wooden blocks on top of the discs to reach the ratchet plate.  You screw the ratchet plate down by hand until it is sitting on the blocks, and start applying real pressure by cranking down the ratchet plate using a metal lever.  The juice gets squeezed out the sides of the basket and into a collecting tray with a spout.  We collected the juice in a large plastic pail.

My wife and I taking turns using the press.

Under pressure, the juice flows quickly.  Of course, we tasted it.  It was the sweetest, yummiest apple juice I have ever tasted.  In fact, it was so much better than store-bought apple juice that it really makes you wonder why.  The kids loved it too, but I wouldn't let them have much.  It is immensely satisfying to hand-pick several boxes of apples and then use your own muscle power to squeeze out 5 gallons of delectable apple juice.

The products of pressing:  apple juice and pomace.

(This post is getting a bit long, so I'm going to write about the apple cider and wine separately.)