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How to use and replace an Italian Bottling Spigot

When I first started brewing beer my mate said to me:

"yeah brewing's good and all but bottling is a real bitch".

I realized they weren't wrong when I once didn't notice the bottling wand had fallen out of the fermenter tap on bottling day and my brew was piling in a nice pool on the shed floor.

Anyways, a bottling spigot is a handy little device that can help make that bottling chore just a little bit easier.

So what is a bottling spigot and why are they often referred to as Italian?


The 1/2 half inch spigot tap is used to transfer the precious beer or wine into the bottles. It's a handy valve to control the rate of transfer and it's easy to turn on and off.

They look like this:

italian spigot for bottling

These spigots are commonly made in Italy from food-safe plastic but the truth is they are most likely manufactured in China. If you a serious about your plastic safety, look for a brand that has been FDA approved.

Note the tapered ending. This is so you can add a bottling wand or plastic tube for pouring (typically good for 5/16" and 3/8" size hose). This is handy if you will be running the brew threw an inline filter.

Here's a handy video guide on how to install the spigot


Taps can break fairly easily but lucky for brewers everywhere, spigots are cheap and easy to replace and install. 



There are some handy hints in the video that are worth mentioning:
  • Screw the unit in carefully. 
  • Remember to attach the gasket from the inside of the fermenter
  • Do a test with water to ensure the spigot is sealed properly
If your fermenter bucket doesn't have a hole for the spigot, you'll need to cleanly drill a hole that is 1" in size (25.4mm). This kit actually comes with a drill bit that you can use to drill the hole to the exact size.

Given the spigot is easily removable by unscrewing the gasket, they can be removed and cleaned quite easily. This is a good idea if you are keen on preventing beer infections and the like.

You can, of course, use spigots for any kind of beverage dispenser or 5-gallon bucket.

Check out what's available on Amazon.

How to make homebrew hard cider

how to brew apple cider

When I was a lad, I lived in a place called 'the fruit bowl of New Zealand', that place being Hastings.

There were apples everywhere, in the orchards, on the farms, on every corner. Open the newspaper and four or five would fall out! 

And never once did I think about making them into cider.

And now that I live miles away from the orchards of home, a good cider reminds me of years apple picking and thinning and driving a hydra-ladder around an orchard to help pay for university fees.

But you came here to learn how to brew an alcoholic (hard) cider, so let's get on with it. 

If you've brewed beer before, it's the same concept of fermentation but with some slight variations to the preparation of the basic ingredients and the addition of a few handy remedies to augment the cider's flavour. 

As always when brewing, it's very important that all your equipment is exceptionally clean and properly sanitized.

So what do we need to begin making hard cider?


If you think the first thing on the list of things you need is apples or pears, well, you'd be right.

But it's not that simple.

When brewing cider, not all apples are created equal.

Ideally, you'll have been able to harvest some late-season apples, maybe even some which have naturally fallen from the tree. This is because these apples have high amounts of sugar in them, and as any brewer knows, sugar is great for fermenting!

Having a mix of different apples is very useful for taste preferences as well. Mixing Red Delicious with Granny Smith in a 1 to 2 ration will produce a dry cider whereas 1 to 2 ration of Macintosh to Cortland will produce a sweeter cider.

Another way to get the mix right is to use a mixture of 70% dessert apples and 30% cooking apples. This should give a good balance of sweetness and acidic taste.

Preparation of apples for brewing


First up, wash your fruit of dirt, bird shit, leaves and twigs and the like. Cut away any rotten fruit as well. If your apples are a bit bruised, this is not a concern. 

Your immediate goal is to turn your apples or pears into a pulp. Some players may use a scratter but chances are you're gonna have to do this the hard way by using a bit of elbow grease and pulp them into what's called a 'pomace'.

What you do is pulp the fruit in a large bucket by simply pounding it with a piece of clean wood in the form of a 4 x 4 post. Or the end of a baseball bat, or whatever's handy for pulping.  Things will work out best if you quarter your apples or pears before starting this process.

You can always use a blender to speed the process along, but you are not trying to puree the fruit so go easy with the blender. 

Bear in mind, you're not trying to go all Charles Bronson on your apples. Your mashed apples should have some substance to them, and the should certainly not be liquefied. If that's the case, you've over pulped. 

How much many apples do I need to make cider?


A very rough rule of thumb is that 2kg of apples or pears can be turned into 1 litre of juice. If you are thinking in gallons, you'll need 20 pounds or just under 10 kg per gallon. So, if you want to fill your traditional 23 beer fermenter, do the maths and you'll find you need 46 kgs of apples. Which is a lot of apples!

When crushing, be careful not to overdo it. The finished apples should have some substance to them, and liquid juice should not be present. If it is you have pulped them too much.

brewing cider tips


It's time to press your apples and extract the juice


Seasoned pros will venture that using an apple press will save a lot of time and efficiently produce a lot of juice. 

Make sure you apple press is nice and clean. Make sure you have a clean bucket properly positioned to collect the apple juice. 

Then load your quartered apples or pears into it. 

As you turn the press, you will start to feel some real tension. Don't be tempted to keep going, this is part is a part of slowness and patience. Leave the press in this position for a couple of minutes and the juice will actually begin to

Turn the press down onto the fruit until you feel some real tension. As soon as you do, don’t keep turning but leave this in position for a few minutes. You will see the juice will start to run. When the juice stops then tighten the press again and leave to repeat the process again until your apples are fully pressed. 

You should now have all the juice you need to make your cider with but first, it's time to add a campden tablet or two.

Adding sodium metabisulphite to kill off wild yeast


Producers of cider know full well that a batch of juiced apples can easily succumb to acetobacter bacteria contamination which causes the classic turn-to-vinegar spoilage of the apples.

Acetobacter is easily killed off, hence treatment with an agent like a Campden tablet (sodium metabisulphite) is important in cider production.

Using approx one tablet per gallon will also see off any 'wild yeast' that might have traveled with your apples. 

Experienced cider conjurers may also take the opportunity to add pectolase or peptic enzyme to the juice. Pectolase aids in the break down of pectin in the fruit giving you more juice and of great importance, this facilitates a better fermentation and a clearer cider as it helps reduce pectic haze. The amount of enzyme to add is approximately one teaspoon per gallon of juice. 

It's also used in winemaking for the same reasons.

It's recommended that you give this new solution 48 hours before you pitch your yeast to commence fermentation. Given this time, you should cover your apple juice will a towel or some such item to prevent foreign particles from getting in. You may wish to give it a stir once in a while as well. 

Adding yeast to the apple juice


Having let your juice rest with the Campden tablets for at least 24 hours, you are now at a fork in the road somewhat. You can take your chances with any benign yeast taking their opportunity to ferment the juice or you can pitch a yeast that is well suited for brewing with apples or pears.

If you didn't already transfer the juice into your fermenter, now is the time to do so. Make damn well sure it is properly sanitized.

You might want to take a reading with a hydrometer to get the gravity of your juice so you can work out the ABV. 

It's time to add the yeast but what kind should you add?

The classic, traditional yeasts to use are commonly referred to as Champagne yeast as they produce what is often described as neutral flavors but there are some great wine and beer yeasts out there to try as well. 

Here are a few selections:

Specific yeasts for cider

  • Mangrove Jack’s Cider Yeast M02
  • Safcider from Fermentis
  • WLP775 English Cider Yeast from White Lab

Champagne yeasts for cider

  • Prise de Mousse, EC1118 from Lallemand. A popular choice for those who wish to have a high alcohol content (and you can encourage this by adding extra sugar to your cider batch).
  • Pasteur Blanc from Red Star
  • VQ 10 yeast from Enartis
  • Enartis Ferm WS

    Beer yeasts for cider

    • Saflager S-23 from Fermentis
    • WLP565 Belgian Saison from White Labs
    • Wyeast 3711 French Saison
    Here's a demonstration video of how the professionals do it:

    How long to leave the cider to ferment?


    Fermentation should start within the week, or a few days if the temperature is ideal. You'll want to let your brew do its business for about two weeks AND then give it another to let the yeast begin to settle out of the solution to improve clarity.

    You can get away with quicker times for brewing beer but apples and pears need this time if you want to make a quality brew.

    What temperature do you ferment cider at?


    As with beer making, sound temperature control will improve the odds you will have a good tasting beer. The extremes apply here - too cold and the yeast will hibernate and not ferment. Too hot and the yeast will be overworked and will produce fusel alcohols which will impair the taste of your cider. 

    The ideal temperature is considered to be about 15 degrees Centigrade or 59 Fahrenheit. Nudging to 20 is acceptable but anything over will produce unwanted side effects. 

    A steady temperature is also ideal. Too much fluctuation can through the yeast off its game. If you have a brewing fridge / fermentation chamber with a thermostat, your cider is ideal for a run in it. 

    When to add malic acid to cider brew?


    Malic acid occurs naturally in apples and plays a part in the pH level of your cider and most crucially taste. If your pH level is too high, then adding extra malic acid will reduce the pH level (remember the lower the pH level, the more acidic a solution will be). 

    Conversely, if your pH level is too low, then you'll want to add a base such as precipitated chalk.

    So then, your next question surely then is what is an ideal pH reading for cider? Many brewers aim for a range of 3.2 - 3.8. If you're nudging over four, you'll want to add malic acid as given it is already present, it matches the profile of the cider. 

    If you're interested in using a digital pH meter for checking the level of your cider, check out our pH tester buying guide.

    Do I need to add tannins to my cider batch? 


    Tannin is a yellowish or brownish bitter-tasting organic substance that can be found in plant material such as tea, rhubarb, grapes and apples. Tannins are acids, a well known one being gallic acid. Tannins give an astringent, drying bitterness quality to cider. 

    Some kinds of apples have high tannin levels so the addition of them is not really necessary. Where brewers are using applies which naturally make a sweet cider, that brew may need some added tannins. 

    A ¼ teaspoon of tannin per gallon of cider is a commonly recommended amount to add. The exact amount can be a bit of a science, this dude has some great advice on how much to use.

    Tannins can be sourced online from Amazon or from your local brew shop.

    bottle conditioned apple cider


    How long do I bottle condition cider for if I'm carbonating?


    Cider takes a lot longer than beer to condition to an optimum drinkable state. It can take up to two months for carbonation to fully occur and even longer for the cider to reach peak performance. That said, some brews will be carbonated within 2 - 3 weeks. 

    It's very important to only bottle when you are sure fermentation is complete as if you cap those bottles before the yeast has done its job, you'll run the risk of bottles blowing up especially if you've added sugar to promote bottle carbonation. A bottle explosion can send a big foamy mess everywhere and littering the place with sharp glass. Trust me, I've made this mistake before and it's a massive pain to clean it all up and worse, it's a waste of time and energy and money!

    If you want flat cider, without carbonation, you'll need to add an additive such as more Campden solution to prevent any residual yeast from fermenting in the bottle. Like when you were preparing the apple juice, leave the Campden to sit for a whole day before bottling to help ensure any yeast present is accounted for.

    Remember to store your bottles in a cool spot, free of direct sunlight.

    I should mention that before bottling should taste your brew as this is the time to 'back sweeten' if wish. If you want to do this, you can add a non-fermentable sweetener such as stevia. This is in place of using extra sugar and it will mean you won't over carbonate.

    Making cider from store bought Apple Juice


    Making cider from store bought apple juice is a very simple process as the hard work has been all done for you. Try and use a juice that doesn't have preservatives as theoretically this can hamper fermentation from commencing but don't over think it.

    You might want to start with a gravity reading. If it is below 1050, then you may wish to consider adding a bit of sugar so the yeast has something to start working on.

    The process of fermentation is the same so fill your clean and sanitized fermenter with the desired juice. Give it a bit of a shake to aerate and then pitch your yeast - maybe Lalvin EC-1118. You could also add some yeast nutrient as well.

    Some brewers split the juice in half and once they are satisfied fermentation is occurring, they add the second half.

    Seal your fermenter with an airlock and leave it be for 2 to 3 weeks at a minimum. When you feel your cider is ready for bottle conditioning, you can batch prime with dextrose in the normal manner.

    You will want to condition your cider for a minimum of two months - cider brewers need to be more patient that beer brewers if they want a good tasting cider!


    What is a Demijohn?


    A demijohn (or jimmyjohn) is a particular kind of glass fermenter that is popular with cider and winemakers. They come in all kinds of sizes from 5 litres through to 23. The smaller sizes allow for experimentation. Their long necks can make them troublesome to clean.

    hard cider beer kit


    What about brewing with a cider kit?


    There are plenty of cider kits out there, just as there are for beer. We've taken a fancy to the Brooklyn BrewShop's Hard Cider Kit:

    A perfect kit for beginners, it makes fermenting hard cider at home simple and fun. The kit has enough ingredients to makes 3 batches of hard cider.

    It includes 1 gallon reusable glass fermenter, 3 packets yeast, vinyl tubing & clamp, racking cane & tip, chambered airlock, 3 packets cleanser, and screw-cap stopper. 

    You'll need to supply your own apples or juice.

    You'll be able to produce 3 batches of 7% ABV of hard cider (9-10 12-oz bottles). Brooklyn BrewShop describe that this kit will help you make a cider that is tart, bubbly and dry. Check out the price  and reviews on Amazon.

    Using gypsum to increase bitterness and reduce ph levels

    gypsum salt for brewing

    Using Gypsum to make hoppy beers taste great


    You may have heard that to lower the pH of your beer water, you can use calcium chloride, it works and works well but if you are looking to make a beer that would benefit from a bit of bitterness, gypsum might be the solution.

    Gypsum's scientific name is calcium sulphate (CaSO4·2H2O) so you can see it's got something in common with the chloride. Basically, it's another handy beer salt. 

    It does do a few things for your beer. If you add it to your mash, it will help lower the pH. A second effect is that the increased sulfate content will help to accentuate the bitterness of your beer. 

    A handy trick is that if you desire to increase the sulfate level to produce a more bitter beer enhancement but don't want to alter change your mash pH level, you can elect to place it directly into the kettle

    In doubt about the pH level of your water? Use a pH meter.

    How much gypsum should I add to my beer?


    Generally speaking you really only need to change the pH if your water needs some assistance. Get your source of water analysed will allow you to make a real judgement about how much gypsum to add, but frankly who has time for that? 

    If you wish to increase the bitterness of the beer, you're going to use it anyway right? This is particularly the case if you need to harden the water as you wish to brew an ale or bitter.

    Maybe that's a bit of a gung-ho attitude but whatever. That said, I did read an idea that pointed out adding gypsum to water which has an unknown status is like adding salt to a meal you've never tried. 

    In terms of adding gypsum, a lot depends on how hard your water is. If your water is low in sulphate and you're making a beer such as an IPA then adding about 7-8 grams of gypsum to a 5 gallon batch is probably all you will need.

    How is gypsum used for hoppy beers?


    Gypsum acts to suppress harshness and astringent flavours. Brewers can take advantage of this to use large amounts of hops without contradicting or causing disharmony with other components of the hop. Don't push it though, too much calcium carbonate with lay this balance to waste.

    What is the Burton Snatch?


    If you're brewing wort or water features too much sulphate, you will get that rotten eggs smell which is sometimes known as the Burton Snatch. This is why it is important you don't add too much gypsum to your brew. To be clear, in the case of using sulphate, this is the cause of the sulphur smell you may get a whiff of and not the smell of an infected beer.

    The name 'Burton Snatch' comes from the history of beers brewed at the place of Burton-on-Trent, England. The water of that area was naturally high in sulphate and when used for a brew or two, excess sulphite would cause the whiff when a beer was poured. 

    The snatch smell, if we can call it that, is now infamously tied to beers brewed using the region's water supply

    Do I need to use gypsum if I am using malt extract kits?


    You probably do not need to add gypsum if you're using a malt kit. Given kits are designed to be the wort you need to make the beer you want to make, it seems unlikely given modern manufacturing standards that it should be necessary to add gypsum. 

    Using calcium chloride to reduce pH of beer

    using-calcium-chloride-ph-level

    An experienced brewer will be no stranger to the fact that the pH level of one's beer has a direct effect on flavour. A beer that is pH balanced will feel good to the palate meaning you've a drinkable beer. If your pH level is too high, one way to reduce it is with calcium chloride flakes.

    By adding salt chlorides to your beer, you not only reduce the pH level but have the benefit of the chloride ions working to promote the sweetness, or mellowness of the beer's taste profile. 

    Charlie Sheen would call that #winning. 

    Using calcium chloride has a variety of benefits for beer production
    • reduce pH levels as needed
    • promotes the water hardness of beer
    • help preserve mash enzymes
    • asssit with increase extract yield
    • improve yeast metabolism growth and flocculation (great for clear beer)
    • accelerate oxalate removal
    • also used in cheese making as a firming agent
    • can be used to pickle vegetables!

    How much calcium chloride do I add to my water?


    General instructions are usually to use one teaspoon per 23 litres / 5 gallons (or as required). It will dissolve best in cold water, especially if it's stirred or shaken quite vigorously. 

    When you think it's properly dissolved, check with a ph meter to ensure the level is as you desire. 

    You can then proceed to use your water for mashing or sparging

    Pickling with calcium chloride


    I recently discovered that you can also use calcium chloride to help make pickles! Have you ever heard of Ball's Pickle Crisp? It's a popular product for when pickling dill pickles - it leaves them firm and hard which improves the eating experience. 

    You've probably figured out by now that the secret ingredient of pickle crisp is that it is one hundred per cent made of calcium chloride flakes. So if you want to save yourself a bit of money from the brand name product, grab a no-frills bag which will cost you less and get you more. 

    #winning. 

    Replace the pressure relief valve if your corny keg is losing pressure

    corny keg relief valve replace

    Is your corny keg losing pressure? Replace the valve


    Are your poppet valves and o-rings doing their job properly keep your brew fresh?

    If they are, chances are your pressure relief valve is failing and needs to be replaced. And it’s important you do so as flat beer is a real, first world problem that can be damaging to one’s stomach and mental health!

    The role of a pressure relief valve is pretty simple and obvious if you can read its name, they exist to let out pressure should your corny keg become over pressured. So you need them as a safety measure.

    The valve will release automatically when the keg itself is at a pressure point of around 800 kPa. This could potentially occur when say you have a regulator fail and CO2 keeps getting sent into the keg. This may seem a bit of a far-fetched example...

    More reasonably, if you need to open your keg for some reason, using the relief valve to remove the pressure is a smart move to avoid spraying beer everywhere. Only beer rookies make that kind of mistake and they only make it once!

    So if you’re experiencing a faulty valve, you can replace it quite simply and cheaply by ordering the part on Amazon and take advantage of your free shipping with Amazon Prime.

    But not all relief valves are the same. Some are made of plastic, some of stainless steel.

    If you’ve ever read any other post on this site, you’ll know we always recommend quality over cheap parts and given steel is more durable than plastic, we think that’s what you should go for.

    The valves come in two styles, the pull-ring or the toggle. You can tell the difference as the pull ring literally has a steel ring that you can manually pull when its installed on your Cornelius keg to release the pressure.

    If you have bought a second-hand corny keg, you may wish to replace the valve just for peace of mind. You could also consider replacing the entire lid of the corny keg, which would include a new valve - but you may not have the budget for that and so the idea of replacing the poppets and relief value if they are tired seems like a sensible precaution to me.

    How to choose the best brewing spoon

    choosing the best brewing spoon

    This next question might cause a bit of a stir but what is the most useful item to have when brewing?

    Is it a big kettle?

    A giant mash tun?

    A ph meter?

    Those are nice things to have and all but we think the most useful item to have ready to hand on brew day is a spoon.

    That’s right, a big spoon.

    A big spoon to stir everything up just right. A spoon to unstick a stuck mash tun. A spoon to stir in hops. A spoon to stir in yeast. A paddle to break up clumped together ingredients.

    Spoon or paddle, it doesn’t matter but the best ones do have a few factors about them that make them ideal for using on brew day.

    They’ve got to be sturdy enough to stir with. Too weak and they’ll snap. This is why some brewers like steel spoons. Many of them have a corrugated design to prevent bending.

    The only drawback is the steel can scratch your gear. If that’s a problem for you, use a plastic paddle if it’s strong enough. 

    If you do choose the plastic fantastic, then ensure it’s food grade quality and that it is resistant to heat. 
    Some of those brews can get pretty hot so if they are not heat resistant, they are more liable to break. Some smartly designed spoons will have a small head on the top of the spoon which can fit inside the next of a carboy which can be quite handy if you want to mix things up.

    Conversely, steel spoons often have a bent top so they may be easily hung up on the side of a kettle or whatever. Else, they will have a hole in the top so they may be hung on a hook.

    A great thing about stainless steel spoons is that they are easy to clean and will not retain odour. Handy if you’re also cooking crawfish or doing a turkey in a brewing kettle.

    Wooden spoons can snap easily and can carry bacteria. No one wants a wooden spoon eh?

    When stirring a mash, some prefer the paddle as they can be more effective in moving the grains around. 

    You will of course what your brewing spoon to be a long enough length so that it can reach to the bottom of your kettle or drum. To that end, a 21 - 24 inch long brewing spoon should generally see you right for your stirring needs. Such spoons will work best with 4 to 10 gallon size brewing kettles.

    As with all brewing equipment, you should only use a spoon that is clean. It doesn’t need to be sterilized when using before or after the boil as the heat should have killed any microbes that may have been lurking about. If however, you need to stir anything afterwards, then you will need to have sanitized your gear (we totally recommend you use sodium percarbonate for this task). This is especially true if you a simply mixing up a beer kit with some beer enhancer as there won’t be any heat to kill the bigs.

    Check out some options on Amazon.

    How to accurately use a refractometer to check specific gravity

    beer brewing refractometer

    What is a refractometer?


    A refractometer is a tool used for measuring concentrations of aqueous solutions. It has many applications across food, agricultural, chemical, and manufacturing industries. A refractometer can be used to measure things like the total plasma protein in a blood sample, the salinity of water and even the amount of water content in honey.

    They work by measuring the angle of refraction as light shines through the solution. Don’t ask me to explain the actual science behind it, I just work here man.

    What I do know is the Brix scale is used as the means by which the measurement taken is assessed. Given we are talking measurements here, it should be no surprise that the Brix scale measures the sugar content of an aqueous solution.

    This is when you might exclaim “Ha! I got you mate, wort is mostly malt sugars (maltose) and not sucrose so how does the Brix scale apply to beer?”

    And I’d say you’d be right and you can account for this learning how to apply a wort ‘correction factor’. Frankly, this can be a bit of pain and is one of the reasons why some brewers prefer to use a hydrometer to calculate ABV.

    Refractometers also only use a very small beer sample, especially less than a hydrometer which is why some brewers prefer them - especially if they are only brewing small batches of beer.

    How is a refractometer used in homebrewing?


    In terms of homebrewing, a refractometer used to measure the specific gravity of the wort before fermentation commences.

    You probably already know what specific gravity is. If you don’t, a quick lesson from Wikipedia.

    “Specific gravity is the ratio of the density of a substance to the density of a reference substance; equivalently, it is the ratio of the mass of a substance to the mass of a reference substance for the same given volume.”

    Simple right?

    In terms of brewing, one uses a refractometer to determine the amount of fermentable sugars which will be converted to alcohol.

    What is the best refractometer to use when brewing beer?


    There are many kinds of refractometers, and they serve different functions. As a brewer, you want one that is designed to measure sugar. Most brewers use is kind that fruit growers use to measure the sugar concentrations of their fruit to assess ripeness. This way you get a close approximation to wort, but it’s not exact and this needs to be factored when using the Brix scale as mentioned above.

    Check out some options on Amazon.

    How to properly calibrate a refractometer for testing beer


    Just like when you use a pH meter, refractometers need to be calibrated.  There’s no way out of this.

    Add distilled water (if you have it) close the plate. Ensuring the liquid to spreads completely across the prism without any dry spots. Allow 30 seconds so that the water can reach the same temperature as the refractometer.

    This is important as the readings are temperature dependent.

    You simply then aim the refractometer toward a natural light source. Look into the eyepiece and adjust it so that the scale is in focus.

    Then adjust the unit’s calibration screw so that the refractometer reads exactly zero.

    Now you are ready to sample your wort.

    Testing wort with the refractometer


    It’s fairly easy to use a refractometer, it’s largely the same process as setting up for calibration.

    Once the unit has been properly cleaned of residue and correctly calibrated, place a small sample of wort on the glass. 

    Shut the cover and take note that the glass is fully wet and has no stuck air bubbles. Give time for the same to warm to the same temperature as the unit.

    Turn the refractometer to a natural light source. The refractometer should be held level with the window pointed at the light source. You can take the reading by checking via the eyepiece. Bob’s your uncle.

    I should not have to advise you do look at the sun directly but as some of you drink and brew...

    Check out some options on Amazon.

    Bonus fact!


    The first refractometer was invented by Enst Abbe. It was a complex device that included built-in thermometers and required a circulated water mechanism to keep the instrument cold. 

    While the devices have been refined and digitised in the hundred years since Abbe’s invention, the principle of how they work remains the same.